To think I don’t have to explain/justify myself to manager?

[Diamondeye]

I’m in a team with two managers but only one of them is my immediate manager.

Due to depression, anxiety and stress and signed off by a doctor I was recommended to return to work under reduced hours (increasing each week) and work.

My immediate manager is fantastic and so supportive.

Yet the other manager is constantly on at me about it ... to the point that I genuinely felt like I was going to be sick from my anxiety today.

Aibu to think if my immediate manager has ok’d everything with me then I don’t have to explain or justify anything to anyone else?

The answer to this really depends on what's been agreed. Get real charity from the manager you made the agreement with sense then you'll know if the other one was being inappropriate.

Yes, discuss this with your immediate manager. It was recommended by the doctor and arranged with your immediate manager, so it's not really any business of the other manager.

Thank you, hate to be a sob story (as we all go through bad times) but I’m trying so hard to be in a good place again ... and this constant justifying and being made to feel shit is making me start to struggle so much

Stay polite, smile and talk to your own manager about this ASAP. You are legally entitled to a safe workplace and if you are feeling pressured and harassed when you are already in a bad mental state it’s not a safe workplace for you.

It depends on what she is asking you. If it is related to work she is accountable for, she needs to be able to interact with you about it to do her job. If not, and she is just asking you questions for the sake of it, complain to your line manager.