How can i escape the emotional abuse?

I live with my grandmother, dad, stepmom, grandfather and two baby siblings. My grandmother is constantly calling me a slut and a and telling me im fat and will never amount to anything. I can;t stand the emotional pain anymore. She makes me not want to live. My boyfriend is the only one who seems to care about me anymore. I'm fifteen. I can't take the emotional abuse anymore. It's really taking a toll on me. How can i escape it. Please be nice when you answer. Thank you