MEAN MOM PLEASE HELP!!!!!!!?

Ok, both of my parents are super strict about grades. I'm not even allowed to get B's! My mom however is the most strict. She's always saying that education should be my number 1 priority in life. Right now I'm in 7th grade and struggling with OCD (obsessive compulsive disorder) which she doesn't know about because if i told her about my mental issues she wouldn't believe me nor would she take me to see a phycologist. She would just get more mad if I told her. I wish I had a kind mom that was willing to listen to my problems and help me fix them. I hate my mom. She puts way too much pressure on me to get straight A's which is especially hard for me with my OCD and all. But somehow i have managed to get principals list on every report card untill now... I got 1 B and an A in everything else. The one only B i have ever recieved on a report card. When my mom found out she was pissed. She doesn't talk to me now and she hardly looks at me. She grounded me and according to her I'm not allowed to go anywhere at all untill I finish the rest of my 7th grade and 8th grade year with all A's on all of my upcoming report cards. That's over a freaking year!! And today she told me not to tell her I love you. What the hell is wrong with this woman!! All this BS over 1 freaking B!!!!! Ontop of that this is the ONLY B I've ever gotten. My mom just expects me to be perfect. And she is always always comparing me to other kids. I've never been good enough for her. All I want are parents that understand me parents that won't punish me like this for things as minor as a frickin B which shouldn't be considered a bad grade in the first place! I all ready have enough problems in school I'm always getting picked on and I have no friends. Why do I have to come home to more problems? I don't deserve this crap from someone who should be my main supporter and best friend, my mother. All I want are proud parents who appreciate my hard work. I used to cut myself and even tried killing myself at one point, because I hate myself for being unnatractive and imperfect and not good enough and different from everyone else. I sometimes feel like killing myself to make my mom feel bad for all the **** she's put me through. She said I needed to get all A's to be accepted into the IB program in high school. Does this one B really mean I won't get accepted? Can anybody help me get through all this?