I was in your exact position. Worked in the ER, did evenings (3p-3a) loved it but eventually the frequent fliers, poor staffing, and constant stress was weighing me down. Never got a break and got down to almost 100 lbs (best diet I ever went on!). It got to the point where if a patient wasn't dying or about to die, I did not care at all why they were there. I just wanted them to leave. I became mean.
Finally switched out to the OR. It was a rough couple of months because I was new to the OR and there was so much to learn and it was very overwhelming. I almost went back to the ER because that was what I "knew" and I was good at it. Finally I got the hang of it and never looked back at the ER. I told myself I would pick up shifts, but I just couldn't convince myself to go back. I actually got a 15 minute breakfast break AND a 30 minute lunch break with opportunities to use the bathroom. I worked twelves and a lot of times we were done after 3pm, so I got to actually sit and relax! Yeah, it got boring sometimes circulating, especially if it was a long case. But I learned how to scrub, and be decent at it, so it was nice to change it up and scrub in every once in a while.
Don't be afraid to branch out - it'll save your sanity. I took a paycut switching but it was worth my mental health. My depression got better and I actually enjoyed working with patients again. Most OR patients are lovely and they're so grateful towards you (except when they wake up wild but that's not their fault).