AIBU to feel upset after my meeting with my manager?

Yes. I worked in a job where they used a very straightforward appraisal system which worked well. They changed it to an American system which used graphs and was very complex. We were not only measured by how well we had achieved the goals and targets that had been set, which I would expect, but also how by much we had gone beyond that in terms of extra tasks and initiatives. This was for a low paid, low level job.

Get as much sick leave as you can out of the bastards, then resign. Build up your pilates business whilst off. You can do it ❤

Don’t do this. You need to maintain the moral high ground and your position as someone who has behaved properly. Do find another job as others gave suggested and give proper notice and leave. They are clearly trying to force you out. At this stage of your life and a stressful minimum wage job it is not worth fighting.

It's a toxic work environment and they are clearly taking advantage of you. You sound like you're working far too many hours. It's not your responsibility as an employee to make up the work of other people. It's the company's responsibiity to staff their business properly.
As for the assessment, I would take it with a pince of salt. It sounds like the business is not replacing people who leave and lots of people are leaving. They are in trouble and they are trying to blame you but in all likelihood, downgrading you is a cost saving exercise and not based on bad feedback at all. Otherwise they would have lots of actual examples.
If I were you, I would leave. Go to your GP and tell them the effect it is having on your mental health and get signed off. Let them manage without you if they dislike your attitude so much. Then look for another job, if you want one, and then hand your notice in. Stop acting as though you owe these people something by picking up extra work, dancing to their tune. You owe them nothing - apart from your resignation to be honest. They sound horrible.

Thinking about it OP, I’d have that meeting with the managers. Go in and say “before you start, have this” and put your resignation letter on the table and walk out of the room. Bugger all they can do.

Whilst waiting for the meeting and during your notice period, work to rule.

I’d have a word with ACAS, I’m wondering if you have grounds for a potential constructive dismissal case.
Meanwhike, you could go down the quiet quitting route, work to rule, take sick leave if your GP will sign you off , and start applying for other jobs.

It sounds like those giving appraisal have no idea of how to do their job. Basically they are idiots. Do you stick it out and do the minimum or do you leave? Only you can decide what makes you happier.

I completely disgaree about leaving. I’ve also been treated badly by manager but I will not be pushed out of a job I am good at. No way will I let the bullies win.

As for those suggesting a supermarket job, wake up! Do you have any idea how hard it is get a supermarket job? Many rounds of application, situational analysis etc, most applications thrown out by AI. Near to impossible.

But they can do it which is the opposite of what you said in this post.

My advice is - leave. For your own wellbeing to ensure they can't get into your head any more than they already have.

But you have a number of options as to how to do this:

1. Get signed off sick with work-related stress, as they have made you ill. I would suggest you consider doing this anyway in addition to whichever of the following options you choose, to give you time to consider your next move. If they were to contemplate giving you a bad reference due to sick leave it could be very risky for them, if the evidence on your fit note indicates they themselves made you ill.
2. Resign. Either a straightforward factual resignation letter or one that clarifies the reasons for your resignation/the fact that they have caused your current ill health (you can stay on sick leave throughout your notice - check your contract to determine your notice period). You could also choose to say you are contemplating options 3 or 4, but would prefer to leave on amicable terms including a positive reference.
3. Raise a formal grievance. Just to point out that it will probably be a difficult and painful process and (given what you have described about the workplace and its management) is unlikely to give you a satisfactory outcome. But it may be useful if you choose option 4, as it will show that you have tried in good faith but unsuccessfully, to resolve things with your employer. It could also force them to produce the evidence to justify their decisions (so it will be obvious if this is flimsy) and you can raise any potential sexism/ageism concerns.
4. Claim constructive dismissal - though in practice this can be very challenging to prove. So you would need legal advice in case you are contemplating this.

I think you need to decide whether to leave this shower behind you and move on with your life, or fight to hold them accountable. That is entirely a personal decision, so please do whichever works best for you. Just to point out that as you are being overworked it is unlikely that redundancy is on the table; it is the job, not the person in the job, which is made redundant. So I wouldn't hold out just for that.

I have only ever left one job with no job to go to but that worked out ok in the end. It sounds like you have put up with a lot for a long time and now is the time to say enough is enough. As pp have said work out how much AL is owing to you and make sure that gets factored in to your notice. Edited to agree with others, if you teach Pilates you have a brilliant fallback career. Impossible to find classes with spaces where I live.

I would leave and I certainly wouldn't agree to a meeting where 2 or more of them can tear my character to shreds. Bad enough they've said it without any actual examples but to then want to pile on is appalling.
I had an appraisal years ago and I knew I was very good at my job in retail always helpful, willing to do anything, friends with colleagues and popular with customers, I was the only one who would stay late or do shifts i didn't normally do to cover staff shortages and my appraisal was that I was just below average. I asked him why that was and it's apparently because they were very big on doing charity stuff and had started helping with a graveyard cleanup every month and I hadn't done it. I told him i had worked a 2 hour morning shift for free while a colleague went to do their bit because I can't physically do that sort of stuff, it wasn't compulsory and not my job to make them look good. He did put me back to just above average but I never worked another extra shift or stayed late.

I would go to the gp and say you aren't sleeping and shaking with stress due to this particular job and get a sick note. That way you don't have to return. Then hand in your notice - how Long do you have to give? Or hand in your notice today and get a sick note or just phone in sick or take annual leave? They must pay you the annual leave you haven't taken

They are shitty managers and its probably not that they want to get rid of you but that they can't cope with managing you

Pilates is the new fitness fashion class at the moment- so make the most of it as in 10 years it'll be something else, by then it wont matter

Pilates is a great option. It’s really hot at the moment, always waiting lists for classes at my local sports centre.

I also got targeted because my boss was jealous of how well I managed my unit

This.

Hand in your notice today, staying will make you ill.

They are piling too much stress on the shoulders of a minimally paid job. I’d hand my notice in if I could or look for a different job immediately

Hi OP, similar thing happened to me. I worked hard and did a really good job, lots of people liked me. Management clearly thought I was a problem and did their best to get me to quit. I was lucky enough to be able to so I did.
I actually looked it up its a real thing people being sacked because they are too good.
Its like that bit at the start of Hot Fuzz when the Met police get rid of Simon Pegg's character because he is making everyone else look bad.
I can tell you its not you its them. Google it, lots and lots of stories, and even in my own acquaintance group two colleagues same firm as me sacked or job deleted so they left, both top quality people.
Take it as a compliment! We are the elite!

I addressed this already. It has to have concrete proof and, in theory, has to stand up in court so most of the employers would avoid giving negative reference as its rarely worth the hassle.

I think you have made the best decision for you and wish you all the best in future.

Given you’ve had no prior history of complaints etc and the profile of the office is younger, you’re now a bad fit.
Not quite “the right sort of person.” The company ethos has changed and you’ve outgrown it.

Reframe your thinking, compartmentalise and get angry. Resolve to do the minimum to keep the job ticking over whilst you look for another job.
Paste a smile on your face and take on no extra work. Let others take up the slack.

Or go off sick with stress. make sure the GP knows and puts down on the form, “work related stress”
Take the full paid time of sickleave then go back for a day or two and go off sick again. They’ve treated you badly so manipulate the system to get maximum paid sick leave.

They should have addressed any perceived performance issues properly and they haven’t

Guess there’s no union or HR.

Work out how you can best cause them disruption while working your way out of the company.

For minimum wage I would just leave. If you get sick pay then call in sick during the notice period, you can self-certify for 5 days. It may not be best to be signed off as unwell if you work another job and continue to attend it whilst sick, although if the roles are very different and you are signed off with work related stress due to your current workplace culture you potentially can argue that your other job is not causing any difficulties.

Are you in HRT? Shaking with stress doesn't sound good, it's like a panic attack. Apologies if you are but HRT can really help with this because stressful situations become more difficult to cope with due to lack of oestrogen.