need some advice

But my sister says how ungrateful i am and how she said she'll support me, and yes she did but despite that she still continued to stress me out on purpose everytime she saw me and she treated me like absolute trash and now because i've confronted her about a few awful things she's done, she hates me and avoids seeing me. She's called my mum up in tears before saying how i apparently told her that my mum "hates her" which i didn't say at all, and she's also told my other sister that i said no one likes her, which again, i didn't say. She keeps lying about what i've said just to spite me. She's also recently mentioned to my dad about selling the house (he was supposed to sell the house when i was out of education) which me and my mum are living in, which means she's making her own mother as well as myself homeless just to spite me. She continuously moans about me and says how no one appreciates everything she does even though she literally does nothing for anyone in the family, she owes a lot of money to both my mum and my dad, and she lets her boyfriend disrespect and say horrible things about my mum. She's making my pregnancy a living hell and i can't get rid of her. She refuses to set foot in the house if i'm there and she won't come to family dinners if i'm there (which is her loss) so i never see her, but she's still ruining my life and ruining me mentally. I have no idea what to do because i'm now soon to become homeless unless we find a place to live within the next 8 months, and even though i don't see my sister, she's still causing me to have mental breakdowns and cry all the time. Any advice would be appreciated, i really don't know what to do