Atheists I need some help with my Christian parents.?

I'm 15 years old. I've been raised to be a Baptist Christian since I was born. About 2 months ago my friends explained to me that god was fake. I told my mom I wad Atheist one day when I didn't want to waste my time at church and youth group any more. She says I was just saying this to hurt her. I told her that is not why and went on to tell her why I thought god wasn't real. She went off and told every single member of my family, the church, her college professor, her classmates, and her boss at work. All these people are Christians so most of them told her that I had some nerve talking to my mother that way. Her boss suggested that she empty my room except for a bed and Bible and leave me alone I'm there until I stop lying. Well she did that and out of anger I used a magic marker to draw Antichrist stars on myself(I regret that). She says she would rather me be shooting up heroine than not believe in God. And now shes threatening to send me to live with my grandmother. Is there anything at all I can do?