Sexual trauma and depression?

My mother and stepdad have sex quite frequently, and it's gotten to a point where I have panic attacks (probably not the right word?).

I've confronted her about this a few times, but it ends with me crying and her telling me me and my sister dont go out often anymore, or that she was just getting massaged, or that I should just put on some music or a video, or that I should knock and tell them to stop. She's gone as far to ask if I watch p*rn or have wet dreams, or if I feel the same if I think of one of my aunts doing it.

I physically cant walk to their door when they do it, I just crumble onto the floor in an attack, and I've tried knocking on the wall (we share a wall) but they dont hear me. I especially dont want to be given the responsibility of keeping two 50 y.o from having sex when my younger sister has friends over.

I hate sleeping in my own house. We live in a small one-story house, so I can hear everything. The sound of their door locked is like a bullet shot by my ear. I cant even lay in my own bed because I can feel the rocking motions. I get paranoid thinking I can hear my mom moaning or my dad masturbating.

It's gotten to where I dont enjoy being around my parents anymore. I dont feel joy when I'm with my mom. I only feel dread. I hate being alone in the car with her.

She refuses to let me see a therapist, as she thinks there has to be something wrong with you to go see one. I tested on the Aspergers spectrum when I was younger, and I feel it could be affecting me now