I think my mom has serious problems, she mentally abuses me.?

Okay, all i ever do is take care of my 6 yr old sister and clean. Thats it. Im not aloud to go to my friends ever. Its been a few months. She looses her pills , she blames me and says im selling/taking them. Im 15. She had a horrible childhood and i think shes trying to make mine bad. On my phone i have a have a "shady list" of all the things she said to me and done in ONE day. Like "I only have one daughter, and her names amy." Yeah, AMY is not my name. lmao. She blames me for everything. She always threating me with the cops and how im going to cause her to drink again. I clean the house, next day, its all screwed up and its my fault. I DIDNT TOUCH ANYTHING! I'll be upstairs for 2 seconds (litteraly) and i here her fat fist banging on wall so i can get her cigarettes and lighter that she left in the bathroom. She decided took take all my nice hollister clothes that my aunt bought me and mopped the floor with them. Withh bleach. WTH right? I cant take it here anymore, I want to just walk out but i cant i have a little kid to deal with and im not going to just leave her with my mom. My moms already made bothsides of the family hate me too. Please help.