Thank you for the opportunity but that doesn't work for me. Then walk away.

What advice would you give a junior colleague OP? Write it down and then apply it to yourself.

Eg: always block out lunch breaks. Be mindful of your capacity and don't over-promise or burnout. You're only one person and the departments reputation doesn't rely on you!

You just have to do it. Write a detailed prioritised to do list, check it with line manager if unsure. Work through the tasks. Do not finish late, stop at your designated time. Repeat repeat repeat.

Give longer estimated delivery times.

You might benefit from counselling if this is a real issue for you, workaholism is a real thing.

Have you told your boss. Asked for a meeting and stated all the things you've listed?
Do you need a mentor? Because if you've got low self-esteem naturally in your personality and those who come through in your work life, so mentor, or counselling, or Careers coach, could help guide you into how to say 'no', and find your other boundaries that are clearly missing.

Firstly you get into the habit of arriving just before start time, leaving Bob on finish time, and going out for fresh air at lunchtime so you are not available.

I'm sorry, but I'm currently working on x, y and x and I simply don't have the time to take on any additional work at the moment...

I really feel.fir you. It winds me up at work when you are expected to do additional tasks, I say it's always as well as and not instead of. Perhaps a Frank word with your boss explaining how this new role suits you re your previous role and why you left? I used to do 111 hour stints 5 days a week plus weekend work- it has impacted in me physically. Remain 100 percent committed during you contracted hours but don't let the old habits creep in. Once u have had the conversation with boss, tell him/her that u will be saying no.not no I can't because as this leads to dialogue. Good luck.

It's your lack of boundaries and tendency to workaholism that are the problem here, not your colleagues. How do I know? Because fresh into a new job with none of the old job's constraints and immediately you have recreated the conditions of the old.

Well done for noticing this and posting.

You have done this on purpose (psychologically speaking) to meet some need that you have. Perfectionism, people pleasing, seeking validation, something.

The good news is, because you created the monster, you can also replace it with something that suits you better.

Think of it as old coping mechanisms that used to keep you safe/get you positive attention but now no longer serve you. Feel free to take control and put them in the bin!

Then discover by trial and error how to live your work life differently. Enjoy!

When you're being given something extra you could try saying, 'I can't do it this week but I could do it next week', and then your boss can decide whether to wait or to give it to someone else.

What always seems to work for me is saying “Yes, I can do X but which of A, B or C do you want me to drop in order to have time for X?”

Go back to basics. The job you’re in now sounds like it’s my level. What advice would you give a junior colleague? This is what I would advise them:

Draw yourself a priority graph - importance on one axis, urgency on the other. Put all your tasks on it and cross out anything in the bottom left. Insist on a regular meeting with your boss, show them this prioritisation and get their approval.

Practice how to say no, out loud and by email, find out where your comfort level is in voicing rejection (and push out of it): That’s not my area I’m afraid, I can’t take that on, I’m sorry but you’ll need to find someone else for that task, No.

Be clear on your responsibilities and other people’s responsibilities. If it’s someone else’s responsibility then it is not your problem, even if it reflects badly on the department. If it is your responsibility, and the total of your (genuine) responsibilities is an unmanageable workload, then you need to go to management to address staffing levels and expectations.

Do you do much in the way of mentoring, social organising etc? I’ve had to get really strict with this. I now take on a maximum of 2 mentees outside of my team. If anyone else asks I apologise that I’m fully booked and refer them elsewhere. I organise one social/extra curricular event per year and bake one cake!

Presumably you took a pay cut when you moved job. If so I'd keep reminding yourself that you reduced your salary by £xxxx to have a better work life balance, so if you work extra hours then you're letting your family down and you may as well not have bothered.

I'd possibly- but you be the judge of that - have a fairly frank conversation with your manager. You're clearly good at your role, so point out that it's important to you to have that balance and that's why you took a step back, so you are going to be making a conscious effort not to be doing lots of additional hours.

Some managers want the moon on a stick. But once they realise it's a choice between having you work proficiently in your paid hours, or taking on too much and potentially being off with stress, they usually make the right choice.

Also sometimes you have to advocate for yourself. I had a project in the summer that involved 18 hr days once a week for 6 weeks. I was - and still am - somewhat surprised and disappointed that my boss didn't make reference to this and suggest I take some time off in lieu. So after that I’m much less likely to work extra hours and will take my own time back if I've worked a lot extra.

Put it back on your boss / whoever is allocating the work.
"Okay, obviously I can drop other things if it is particularly important this is done by X date, but then the other things aren't being done. Which do you want me to prioritise?"