omg I have the same situation... but prove to her that you are capable of succeeding or talk to her tell her how you feel when she yells at you
i am having the same situation. its gonna hurt everytime she yells and says things that feel downgrading to your progress but like @crummybustard6 said you should talk to her and tell her how you feel. cry even. but make sure she knows what she is doing to you and how it is affecting you. don't say you aren't worth it because you are alive now and have the oppertunity to show her your worth and prove her wrong. it worked for me so give it a try.
i experienced the same thing just last night. I feel as broken as you feel. just try to ignore her and everything else and just try to work hard. thats what im doing and i feel ok. and thats better then i what i normally feel. or talk to a close friend. i dont have one but perhaps you do. :)