Help me make a difficult decision

Alright, lets get one thing strieght. This question is not fueled by an argument or a childish reaction to not getting what I want. Through my entire life, I have been forced to live in a house that is literally rotting from the ground up. It is infested with roaches, there are holes in the bathroom floor and living room ceiling, and the kitchen floor is sinking in.

This is not the end of it though. My parents and grandmothers are all mentally unstable and worsening my own conditions as well as my sister's. I myself have been clinicly dignosed with depression, anxiety, and a social phobia. Roughly four months ago, I was hospitalized for my issues, and was at the time cutting and having suicidal and homicidal idealiazations. As for my sister, she has a rare birth defect that involves learning disabilites, chiari malformation, and hydocephalus.

What I'm getting to here is, I am stuck between a rock and a hard place. My therapist, who I will call Sara, has given me an option to escape. I could leave to stay with my 2nd cousin, who lives roughly 200 miles away from where I live now. The problem is, I am terrified of what will happen if my sister and I leave. My dad is a drinker and my mom is a hoarder, and their relationship is already on shakey ground as it is. I may not be as attatched them as I should be, but I do care for them and I don;t want to hurt them. On the other hand, my aunt has her own issues and two kids with similar problems as my own. I would rather go with my great aunt, but she is already raiding her own grand kids, she doesn't need anymore trouble.

I don't know what to do. I need an outside opinion. Help me, please.