Help me cope in a fast paced work environment

Have you actually said you have too much to do? If you keep working late to finish they will think you are fine and coping

Sorry to hear you’re struggling. Is it more that you don’t think you’re managing your time well? Is the work too challenging or is there just too much of it? If you’re having a series of deadline conflicts I would talk to my line manager, and ask for some help with prioritisation.

You need an honest conversation with your manager, what support are they giving you?

What sort of line of work?

What takes the time because the answer to that helps to answer the question about how to handle it.
Is it simply too much work? Keep a log for a bit and speak to your manager
Do you keep double-checking yourself so things take ages? Check less, or only review things at the end rather than going over old ground.
Are you not given everything you need to complete tasks (so have to wait)? Can you align better with those that input into your work?

Above are just some reasons ,but it isn't necessarily your fault. Identify the reason(s) and then tackle them one by one.

do you take more time than your colleagues?
do you know your tools well and know the best short cuts?
what do the colleagues tellwhen you meet up for 'coffee'? maybe they are better at masking than you are?

top tip: take breaks, start end end the working day with a short walk (or other exercise.
and ask colleagues for advice wrt software shortcuts and other things that could help with the work.

I use a Pomodoro timer to keep me focused on tasks where there’s a lot of thinking and writing to do. I make sure my phone is away and that my email is closed. Apparently emails are a killer of productivity and we should only really be checking them periodically.

Is your particular job dependent on you being reactive? If so, you might talk to your manager about the balance of time and priorities.

Have you been there less time than your colleagues OP? 19 months is nothing to sneeze at but you won't necessarily be as efficient as someone doing it for say, 5 years. I don't think it sounds like you are failing. I bet you are doing better than you think.

I started a new job and a month in they dumped a ton of work on me in excess of what I'd been told to expect. I did have an honest talk with my manager and they have slowed it down a bit for now.

Everyone has their own pace OP, and I think you are stressing yourself out by comparing yourself to everyone else. You just focus on doing your job as quickly and a accurately as you can. And if it's not good enough then so be it, at least you know you tried your best. I would guess you are not the only one in the dept who feels this way. Some people are very adept at masking their insecurities and short comings, and that makes others believe they are more successful, when it isn't necessarily so.

How do you know the others aren't also working late into the night?

It is hard to give much helpful advice without knowing what sort of work you're doing (though obviously you don't want to say) but what tools or techniques do you already use to manage your tasks through the day?

How would you feel about telling your manager you're not coping?

Speak to your manager. They are taking the proverbial. Everyone could be working unpaid overtime.

19 months is a little shy of 2 years, when you have more employment protection. So I would not rush to raise this with management yet if you can cope for a bit longer, but in saying that, you must put your health first.

My son's been doing hours of overtime at home for the same reason, new manager seems to think she can speed people up like a bad 1920's movie.
He ended up having 3 months off with acute stress. It isn't healthy to work like this.
I work in the NHS and have never managed to catch up, we are fire fighting every single day. But then I've done it for 40 years so it doesn't stress me out any more.
I agree with others, see if you can make it to 2 years for better employment rights then approach management and say you can't keep up can they help.

Can you keep a record of the tasks you do and how long it takes you to do each one so that you can ask colleagues how long it takes them to do x or if you do decided to go to your managers you have effectively already done your own time and motion study? Is there any adjustment made for dealing with issues which come up and take up time during the day?

Its possible that because you are conscientious you are doing the job properly but your colleagues already know that the work load exceeds what can be achieved in a day and have found ways to cut corners without being found out.

I had a job like this once, I asked the manager if I could sit in with them to observe how they would do the work (this was appropriate because of the nature of the work) within the permitted time, they took as long as I would have done because when observed they did the job according to protocols. There were several of us who started at the same time, many of us could not make the work fit and when we asked those who could they admitted to cutting corners in ways that I would never have considered acceptable, I left.

Are you able to delegate anything to anyone else? Have you thought long and hard about ways of changing the processes to make them quicker? Are all the tasks absolutely necessary? Do you need to attend all meetings? I would definitely talk to you Manager and be honest. If one of my reports came to me and told me about this I would work with them to find a way to reduce their workload or help them manage it and change the team structure slightly. If you are trying your hardest you have nothing to be ashamed of or to worry about by telling your Manager something isn’t working. I would definitely want to know if you were working for me.

What dept are you in ?
This can happen a lot in finance and project delivery teams I’ve noticed

I’d start by facing the problem a bit

Keep a diary for a week , write what you did every day
What was easy
What was hard
And where your day was thwarted by others

Also can you talk with a trusted colleague who does same role and seems to cope ?