I Don't Know What To Do

So I've been in a bit of a pickle for a very long time. I live in a very Christian African American household. All my life has been about control and molding me to be what my, at the time, single mother wanted me to be. So imagine it didn't go over too well when I came out to her. I had been in the hospital for a long time before this, and my mother and I were clashing about my therapy and whatnot. She didn't want to listen to what I had to say under the premise of me "not using the right tone". Anyway, that's how I came out to her, in an argument of tears. And she said it would be okay, and I was happy for I second because I believed that she accepted me. I WAS WRONG. She was only saying it would be okay because she believed she could pray this out of me.
That's when her true colors began to show. She married my stepfather and things got worse. He did things such as threatening me, invading my privacy, calling me names and tearing me down. He still does, 3 years later. And my mother does nothing. She makes constant excuses for him while she gets upset and ignores me for days over the smallest thing. She makes me clean after him like a maid and it's driving me insane! I tried coming out to her again and she threatened to beat the shit out of me. That's when I knew I could never talk to her freely again. I never thought it would have to be that way with my own mother.
Then I tried sending her links and articles and talking to her about it as a means of educating her. That lead to her telling my stepdad and him calling me names and tearing down my self esteem while she sat there and did nothing once more, putting it on me for not sticking up to him, even when she knows that he tells me to shut up whenever I try to do so. So now it's just swept under the rug. She still gets mad and berates me for nothing, she lets her husband do whatever he wants, and my mom is still unwilling to relinquish her harmful mindset, even for her son. It's driving me insane because I have no one to talk to. Even now my mom keeps forgetting to reschedule my therapy appointment even though she knows I'm suffering. I feel sick to my stomach every time either one of them talks to me. I just don't know if I can make it until I can move out.
Any advise would be appreciated.