Please help.. There's no escape.. I can't take it..

PLEASE read this. I know it's long but I'm sorry. I'm so desperate for help.. Please help me!! But please no bashing!!... I'm 16 years old with a 4 week old baby girl. I'm living with my 18 year old fiancé at his parents house... I NEED OUT. I've been living here for about two months and I'm so miserable. My fiancé just treats me like shit and his mom takes his side of course. Last night all three of us got into a huge fight. His mom was yelling at me, calling me a bad mom, saying I don't care about my daughter, and my fiancé just tagged along. They both just gang up on me and I can't take it! I called my mom to pick me up, and I was gonna take the baby with me. I was just gonna go back to my house and spend the night and his mom wouldn't let me leave the house. She said she would call SRS and get a lawyer to have her taken away from me. I just wanna leave. I'm so trapped and so miserable. Please don't judge me, but I used to cut. A lot. I stopped when I found out I was pregnant. All this stress is making me want to cut again. And I feel like I'm gonna lose it. I just wanna move back into my home with my daughter! Without her getting taken away from me! I'm at the point where I don't wanna be with my fiancé any more. At all. No relationship whatsoever. But he'll get mad and just get a lawyer to take her from me! I'm so trapped!! I can't take this! There's no escape! I don't know what to do!.....