Corvid and Leed are right; any power that she has over you is what you give to her. Don't take that abuse, from your stepmom, your sister, or anyone else for that matter. Your stepmom sounds a lot like mine. Just because they're your family doesn't give them the right to treat you that way. Hopefully you'll be able to get away from them so you can raise your son in a more healthy environment. Best wishes to you.