How to get over someone being so terrible to you?

I've been told to grow up and get over it. I've been told I'm a brat, bitch, and a cu*t. I've been told I'm immature and irresponsible.

I'm 21 years old and yeah, while I'm not 100% independent and still rely on my parents a lot, I'm still an adult. I am responsible and I am most certainly not immature.

I've been hit once and slapped in the face more than a few times. Backed into a corner, wrists grabbed so I cant get away, pulled back when I try to get away, screamed at.

This was all because she was in a bad place. She was majorly depressed and had a lot going on, that was her excuse.. She went through a lot that caused her to be angry, but that's no reason to abuse your defenseless sister. She was bigger and stronger than me and knew I wouldn't stick up for myself. She knew I was too scared and weak, but did it anyways for 2 years.

I have PTSD from my own sister, how messed up is that