Had enough

So I’m 17 and pregnant. I live at home with my mum and brother and I planned on my son staying with me here. I’ve always wanted my mum to be around my son because my mum has never met her other grandchildren and this would be the first she meets. Everything started ok she came to my appointments and scans. Now her boyfriend has got involved, everytime they call she talks shit about my boyfriend and then lets him talk shit about me and my unborn son. I told her if she talks to him I’m leaving when I’m 18. I feel so depressed and let down because I don’t know who to turn to. I’m scared to let my midwife know because she wanted to get social involved at one point because she was worried I couldn’t provide but I’ve proved her wrong obviously. My boyfriend wants me to move in with him when I’m 18 (4 hours away from my mum) I really plan on doing so as we have a kid together and my mum isn’t helping me feel any better. Her boyfriend lives with another woman and it upsets me she lets him control her. What do I do? Do I sit down and say what to her? Do I stop her from helping me when baby is born and just learn now while pregnant? Do I stop her from coming to my appointments and just go with my boyfriend? I don’t know what to do it’s like she cares about her boyfriend and not me. He always says oh she doesn’t know how to look after a baby, her and that baby is gonna ruin our relationship because she’s gonna keep pestering you. And once he said if he ever moved in he would put me and my brother out on the street. My dad has passed and all my other family members are no where to be seen. My sister doesn’t like my mum and has kids of her own and there is no room where she lives.