Why is getting raped traumatic?

I genuinely don’t get it. I was raped several times at 16 by someone I was dating at the time. I didn’t realize it was rape because I was conditioned to think that your partner can have sex with you whenever they want, even if you say no. But it still impacts me 9, almost 10 years later. I have specific triggers, I/my body can’t relax around others, and sometimes I cry after masturbating. Why is it traumatizing? I didn’t think I was going to die. I just don’t get it.