Can’t leave abusive house because I’m too young

Location: Alabama
I am in desperate need of help on how to go about escaping a terrible life situation. A quick summary is my mother and her boyfriend are in active addiction and I can’t take it anymore. I have no idea how to leave without her forcing me too come back due to the fact that I am a minor (under 16) and she has full custody. If I were to leave I would live with my brother and grandparents across state. Someone please help me get out of this