Stressful family situation, please help.

Thankyou for reading, this is long but I really need help or any kind of insight.
So i am 24 and 25 weeks pregnant. I live in a house with my nana, papa, brother, sister and mom. My nana and papa own the house, and we moved in because my mom is terrible with money. Anyway, when I found out I was pregnant I told my nana first. She was super excited and as willing to help me with anything I needed. She knew I would be living there since housing is expensive. My mom was the same way. My sister however, is super jealous that everybody was so nice to me and she expected (and wanted) everybody to be rude because she wanted the drama. She keeps making rude remarks towards me and puts my nana through hell with her attitude saying I get "special treatment" (I dont, I buy everything myself). She keeps saying shes gonna go out and get pregnant so she gets special treatment too. Today she made a comment asking how far along I was (25 weeks), and she was like, "oh its still legal to get an abortion my friend and I looked it up". Like, she fully knows im not aborting MY baby. She also writes rude statues about me on social media saying things like "If you want everybody to be nice to you for no reason, get pregnant", "if you wsnt special treatment from nana, get pregnant". My mom wants to take maternity photos of me and shes like "omg, you're all so embarrasing". She also keeps saying under her breath how my baby is an inconvienience. I obviously didnt get pregnant on purpose and ive been trying to work as hard as I can to give my baby a good life. I would support her if the same thing happened, so it hurts that she wouldn't do the same. She made my nana really cold towards me because now my nana is scared to show her "niceness" towards me infront of my sister. She also sends me rude texts throughout the day while im at work. Im really stressed out. She's acting so immature and shes 23 years old. I realy wish I could afford to live on my own because shes really toxic. I fear for when my baby is here cause shes probably gonna get worse, and I really dont want her to affect my sons life. My boyfriend and I were also talking today about health complications in our family and she would be like "Wow, you both are really thinking deep about this baby..."in the most sarcastic tone. She also texts her friend everything that goes on because they "like the drama". 
Thanks for reading this, I really need help, im really depressed.