Can't get along with mom and boyfriend

I can’t get along with my own mom and her stupid 25 year old boyfriend its not even funny at all. She makes me feel like crap coming out of her a$$ I actuallly have come to hate her and her boyfriend at the same time I loved both of them enough to give up my own room so they can move in and pay the bills. I had to sacrifice my room for them and live with my sister, If you can, look at one of my questions that says my sister is a biotch you’ll hear how horrible she is. anyways I feel like I regret givin up my room that I had for barely a year and went to share again with my sister. All three of them treat me like a sack of poop. My grandma says I’m just like my mom and she has an additude, I have an additude when people push my buttons but it seems like everything I say in general always makes me a “smarta$$” to her and she threatens to smack me or worse, get my grandpa to spank me and he hits hard. I cant say anything around her or her boyfriend because everything offends her and he goes off and puts words in my mouth telling my mom that I called him this and I called him that and she yells at me, and when he hits me and calls me fat and cuss names and I charge back she yells at me. shes turning 36 this month and hes 25. like my grandpa said HES JUST A KID LOOKING FOR A$$ They treat me like sh!t. and the worst part is, I hardly get any affection from her anymore, no pet names, nothing. she saves all those for my sister, my brother, and her supid boyfriend. But for me, CINDERELLA!!! OR YOU BETTER CHANGE YOUR F*CKING ADDITUDE VIVIANA OR I’LL CHANGE IT FOR YOU!!! but sometimes I feel like telling her that shes a bad mother or slap me see if I care. I NEED HELP PLEASE IM SUFFOCATING HERE!!