I've been where you are, once about four months ago and once six years ago. Both times I stayed longer than I should have. Both times I hit the same burn out symptoms you describe: hating my daily grind, barely limping through the day. Both times I ended up quitting and eventually landing on my feet at a new job. It can be really hard to walk away, but the damage you do to yourself can really hard to walk back if you let it go too long.

It can be hard to find a fulfilling/challenging/engaging job and it's equally hard to find companies with a culture that doesn't slowly eat away at your sanity. If you can find the latter, it makes a menial/less interesting job better. It's a great deal if you can find both, but it seems like a cultural fit is more likely to help you through what sounds like a very tough personal stretch.

Getting some advice/support is always a solid option in circumstances like this. It might be a former co-worker, a former boss, a family member; whatever works to give you a positive nudge in the right direction.

Another thing I'd recommend: try to find some solace in hobbies or personal interests. If it's a physical engaging activity, so much the better: hiking, climbing, biking, lifting weights etc...It has served me very well over the years and helped me through some rough patches in my own life.

Good luck out there fellow traveler.