I think I was sexually assaulted.. (TW)

So. My mom's been dating this guy for a really long time. And, I've always not liked him but I pretend to for her sake. Well, specifically a few days ago, he came into where I was sleeping, but I wasn't asleep. I was lying there with my eyes closed and I felt him start rubbing my back. He then stuck his hand in my pants and touched my butt, and he stuck his hand up my shirt, rubbing my stomach and my breast. He said I was "so pretty". And, he's a bigger guy and I was way too scared to even react, but I did jump up after he rubbed my breast and go to the bathroom. It's not the first time he's done something like this either. I once woke up to him straddling me between his legs, and rubbing all over me. Once I woke up without my shirt on. I had been wearing a tank top underneath it, but I still felt like I didn't take my shirt off. However, the last one may just simply be me forgetting I took it off, so I didnt think much of it. But it's not only all this, he says really creepy things to me/about me too. He's even said he would date me if he could?? It's so creepy. And ever since the most recent situation I've been really scared to have anyone touch me, or to even be around him. I'm even scared to go to sleep because I'm afraid he'll do something bad to me. I keep panicking during school and stuff too, because I cant stop thinking about how he violated me. I don't know much about sexual assault and I thought maybe I was way overracting and I should just stop thinking about it. But I can't, it's making me feel so anxious. I don't really know what to do.

You were sexually assaulted. Tell your mother.