I am the scape goat and I feel crazy

So here is the background: I am the scape goat and have always been blamed, punished, criticized, manipulated, shamed and guilt tripped by my nmom. She blamed me for all her troubles including my dad's alchoholism. My nmom then married a psycho path for my stepfather. He physically and verbally abused me and my nmom would then blame me saying I got in his face. I will share some specific stories soon.

My stepfather had children that came over split custody and they were favored and not abused. My older sister (GC) did get some abuse (she was thrown down the stairs) but was always gone somehow and is in a lot of denial. I am in therapy and I have recently gone low contact with my nmom and sister and no contact with psycho stepfather. So here is my rant, my mom is sending group texts from her vacation and all the other now grown children are responding and are so happy and proud and planning get togethers and all of that. I am the only one not chiming in because I feel sickened and I feel crazy and like I must be somehow wrong. No one thinks that it was really all that bad and that I just need to get over my PTSD and stop being hurtful.

Are there any other scape goats out there that feel crazy?

I know somebody is going to say I should go no contact with all of them, but I don't want to do that right now.