If at all possible, I'd try to arrange for a break.
A lot of this sounds like it may stem from burnout (before getting into any more long-term conditions). Taking a break probably won't help you see your job in a new light (some jobs simply suck, or aren't a good fit for people personally), but it could give you time to rest enough to look for other opportunities. However first and foremost any such break should focus on resting and recovery to get you to a better state to just be well and happy.
Once you know you can sort out breaks and recover, you can set aside more time to look for opportunities. Right now it seems almost like this may be among your best options: carve out breaks for yourself to rest and recover. Once you're feeling better, take time you've reclaimed for yourself to seek out opportunities to change jobs and improve your work situation.