Why is this happening to me?

Ok, I feel like a normal teenager, but my mom is not letting me grow up. She wont let me do anything. I cant text my friends or talk to them.(there are a lot more things) I feel depressed all the time when Im at home. School is my safe haven and the only place I can feel happy. If my mom is in a bad mood, my simple questions turn her into a bull and she asks for reasons why I am so careless and why I only think about myself. I have had to give her my cellphone, camera, and ipod all because I asked her If she could help me with my math homework. She called me stupid and I have been called a biiittt ccchhh and a little shi ittt many times. She says she regrets having me. I am emotionally abused by someone who I thought would love me and encourage me, not bring me down everytime I did a simple mistake, lost in a competition, got one problem wrong on a test, or even texted my friend in front of her. ( I now have to leave my phone downstairs and pic it up every morning) She acts as if everything is ok and then all of a sudden her mood changes and I am the one who has to suffer through it. She asks me why I make her say all these things, I jsut have to say I will stop being the way I am and I wont do anything bad again, but I dont know what I am doing thats “bad.” She doesnt know that I have tried so hard to just be normal and everything I do has been twisted and turned around by her. What is wrong with me? what did I do? What should I do?