Living with my sister

So I need some advice.
I’m currently pregnant with my rainbow baby and due to some issues I’ve had with my old neighbors for the past 3 years my 8 year old and I are living in my sisters basement.
I’m trying to get my mother to come up and help me get some papers turned in to try and get out of here and it feels like she doesnt care.
My ex husband wont come get my daughter to help get her away from all the stress. His new wife is pregnant too and he has a son so it makes her feel like they dont care if shes there or not.
My nephew runs the house. His dad will tell him bedtime and he would look at his dad and say “no not yet” and his dad would listen to him. If they do try to punish him he acts out more and will even admit hes acting out more because of the punishment so they give in and end the punishment.
My niece is younger and has more rules than him but she still demands things and will throw a fit if she is told no. I dont know how many times my daughter felt like she had to play with her because she was throwing a tantrum after my daughter told her no.
Last Christmas my brother in law tried hooking up with me while my sister was at work and I havent told anyone but my ex/father of the child. And the possibility of that being an issue is stressing me out. I am almost in my third trimester and it feels like I’m alone in all of this. I want to leave so bad. Like if I was given a place tomorrow I would be out. I feel so stressed here but this is the only place I had that I could go. To keep the peace between me and my family I told the father he cant be in the baby’s life so he hasn’t even tried to become attatched (he knows what my reasoning is and that’s why hes not fighting it) I dont even have anyone to talk to about it. I cant even be excited about this pregnancy because no one else even cares about it. What do I do? How do I fix this?