What should I do about my mother?

Background Trigger Warning — I was abused by my brother (anger issues) to the point of fearing for my life when I was 11 years old up til I was roughly 13 years old. My dad emotionally checked out at that point and never reconnected with me (currently 20 years old). About 3 years ago, my mother decided she wasn’t happy with her 21 year marriage to my father and separated from him but wasn’t legally divorced until this year. I was the tool and the middle man for most of the divorce and it was hard on me to be the negotiator. Prior and during that time, my mother became my lifeline as I became suicidally depressed and crippled by other mental illnesses such as PTSD, anxiety, and food issues (complete lack of appetite). As of almost 2 years ago, my mother started dating a man we will call Clark (because my mother thinks he’s Superman).

As for the main issues, I’ve been getting back on my feet rather well with the exception of one area; my living arrangement. I currently live with my ex-abuser and my father and my mother has unofficially moved out with no desire to seemingly live at the house I grew up in, even when/if my father moves out. That creates a big problem because my safety net is now being ripped out from under me. I had planned to stay at the house for a couple of years like my mother promised but now everything has changed. When my father leaves, she will sell the house to go live with Clark so now I have two options; live with my father who I don’t really trust and would have to take care of and potentially my abusive brother or I move in with Clark, his mother, his two kids whom I’ve never met, and anyone else going to live there which also may be my abusive brother.

My current job doesn’t allow me to have an apartment because I can’t pay for it. I was going to use the couple of years I was reassured that I would have to get a job that could pay enough for me to move out, but now I’m stuck between abusive and distant but familiar or disconnected and completely foreign to my entire upbringing (Clark runs a strict household and is seen as the head of the family, I was raised to be equal with my parents as another living person).

That’s not even the beginning, she has completely changed as a person to the point that I don’t even really recognize her. She has completely turned a dime on its head and done a 180° with her personality and that scares me.

I just... I feel like she abandoned me. First my father abandoned me when I was 11 years old and now I feel like my mother is abandoning me to go live her life separated from me.

I understand that I’m an adult now and things change, but I barely see her or even recognize her now. She makes me nervous, not comfortable.

Now I’m just floating with uncertainty and I’m scared.