I was in a crappy job over the summer. I had just finished graduate school and the market for teachers in New York SUCKS and if there are openings they want people with experience. So I took the first thing I could—an assistant teacher position in a year round pre-k. They didn't disclose the amount of responsibility I would have in the interview and it really wasn't worth it for the low pay and long hours. I would come home tired and stressed and it wasn't long before I realized that it just wasn't worth it to stay.
I know how you feel, but I'm glad to see you're focusing on some of the positive. No matter how bad the job is you DO learn from it most of the time (even if it's what to look out for next time around) and you said you're getting better at brushing things off. You're also learning to manage your stress. So even if that's ALL you take away from this job, at least you took away something.
I learned a lot at my job too and it's helped me at my new one. Still, I don't think any job is worth going nuts over, but if you do have bills to pay it can be rather difficult
I channeled my hatred of my job and used it as fuel to search for a new one. I found a much better job as an actual teacher making more than twice an hour what I did at my previous job and I have less responsibility, fewer hours and less stress! As soon as I found out I was hired, I quit my job the next day. It was halfway through July so I had a nice, month and a half vacation until I started teaching in September.
I know it's difficult right now, especially for people our age
but for your health, search for a new job and leave as soon as you can.