confused and upset about sexual assault

Last week, I believe I was sexually assaulted. I went over to a guy's house and he essentially penetrated me without my consent and continued even when I asked him to stop several times. I keep questioning what it was. Like if it was even legitimate enough to be as upset as I am about it. I feel like genuine shit honestly and I'm about to drop out of college just to avoid seeing this guy around. Whenever I think of it I get very anxious and want to throw up. Has anyone else been through this? Any support that can be offered? Thank you