I was in a similar boat last year and went back to counselling for some coping strategies. The most helpful things for me were constantly reminding myself not to worry about things out of my control, remembering that I couldn’t possibly be inadequate because all the evidence said I was doing fine (good reviews, good feedback, not fired!), and keeping a thought diary. Every time I felt down or overwhelmed or frustrated, I’d write about the situation, list my thoughts/feelings/behaviours, and then run a critical eye over them to try and rationalise them and work out where I was being unfair on myself. The more you do that, the more you can notice negative thoughts in the moment and put a stop to them, which stops the bad mood before it even starts. YMMV but as someone with a serious self-hate problem, that worked well for me.
It also helped keeping in regular contact with management and stakeholders to update them on delays. I’m prone to blaming things on myself and keeping everyone else informed takes the edge off of that, makes me feel less like I’m…I don’t know, hiding my poor performance, and more like everything is a group decision. “Okay, XYZ is late, but I told them PM it would be and they didn’t do anything to help so that’s on them…”
Kept me sane for an extra six months, until I got to a place where I felt able to look for other jobs. Hope things get better for you, or that you’re able to get the hell out of there soon.
I used to suffer with broken sleep, and my partner complained about my snoring and heavy breathing keeping him up. Ended up getting tested for sleep apnoea but it came back negative - turns out I just had uncontrolled asthma. I take a preventer inhaler now and I sleep like a log. It’s made it so much easier to get through the day.