Im 16 7 months pregnant and am forced to live at home?

i had a question up but maybe i should rephrase. me and my b/f have lived together in a house that he is buying for 9 months. we had a argument and my grandma and mom freaked out. and now they are forcing me to stay at their house. i have been with this man for 3 years and counting.....how can i go back home with out causing legal problems for him and by the way he just turned 21 last week. what are my legal rights? if you just want to be a smart *** to me dont waste your time it dont phase me i need real help please.