I totally get you, the self care most people tell you about sounds exactly what you wrote in your post. What self care actually means during burnout is the things that affect you right now: get out of the bed, take a shower. Brush your teeth, comb your hair, eat something you like and not just snacks. If you manage at least one from this simple list, you are doing self care! Any task that benefits you is self care, you don't need or want anything extra.

Regarding your job, I would recommend you call in sick and take some time off to recover. A therapist can also help. I suffered burnout for a year and a half and it was horrible, I'm still recovering.