Would this be considered as sexual assault?

I stayed at my aunts house the Thursday before Christmas weekend.. that night my cousin had smoked a lot and as we were going to sleep he asks me, “do you have porn on your phone?” I told him “no that’s gross go to sleep” I turn around and I hear him typing on his computer. Mind that he usually will just watch movies or play music before going to sleep. I hear him taking off his socks and I hear the computer. He was watching porn (while I was right next to him) . I feel the bed start to shake and in that moment I just froze. I didn’t know what to say or do. Then, he sighs and says, “are you up? Are you up? Help me out” I didn’t know if I was imaging this happening or not and I was stupid enough the answer back, “what????” He then says, “help me out. Help me cum.” He said it a few times and I froze. He started brushing his hands on me. And begins to touch me. I finally moved and told him “you’re disgusting!” I went to another room and he followed as asked me not to tell anyone. Then, he stands in the door way as I lay down in the other room. 10 minutes go by and he comes back in and asks me, “what time are we getting up tomorrow?” And as he asked me he was touching my lower back. I’ve only told my boyfriend about the part where my cousin was touching me. No one else. But I’m just confused.. is this even sexual assault or an i being dramatic??? I feel sick to my stomach when I think about it, I still feel like I can feel his hands touching me, I feel gross about myself, and I also feel like it’s my fault like I shouldve done something to prevent it from happening.