first off, ((((((((((((Distressed2010)))))))))))))
This IS abuse. It's emotional abuse. I went through the constant put-downs myself with my own mother, and it's taken me a long time to realize that it's her problems and not my fault. So kudos to you for realizing that already!
How old are you? Are you able to live on your own? You need to get out of that environment. Your mom seems like a horribly toxic person! If you aren't old enough yet to live on your own, can you talk to a teacher or counselor or someone else? Or call CPS?

I know it's an incredibly tough situation to be in, it sounds like no matter what you do, it will be "your fault"