I so totally know how you feel I felt like I could've written your post! I'm living with my mom right now and she's constantly telling me how I'm taking advantage of her (even though I pay over half of the household expenses and she's not working). She can only see things as how they affect her, and that becomes very tiring.

I don't know what your situation is, but my mom was the only family I had growing up and I quickly learned I didn't really have anyone to rely on but myself. That makes it very hard when I'm having a tough time, because when you are all you can count on it takes enormous energy. Eventually I feel like I can't even count on myself, so what's the point in going on with this miserable life....?

I hope maybe you CAN find a way to take a break.....or ring a friend and vent to them, too -- you need some reassurance that her behavior is upsetting so you can feel justified in your anger!
Good luck!