Brothers friend touched me innapropriately ****Trigger Warning****

When I was 10, me, my brother, and my brothers friend were at my house while all our parents went out to hang out. My brother (12) went to the basement to play games, so it was just me and his friend (also 12) in my livingroom. So my brothers friend (lets call him Jay) asked me if a wanted a piggy back ride, I gladly said yes and it was a normal piggy back ride, my arms wrapped around his neck, and him holding my legs. After I got off like 25 minutes later, he asks me if I wanted another piggy back ride, I again say yes because I'm literally 10. So I get on, but he wraps his hands around my butt now instead of my legs, I'm a little confused but just go with it and hold on tight. He starts to fondle and grope my butt, and later he starts fingering me through my shorts, he did this for like 5 minutes and I didnt stop him cause I was just confused. I thought this was wrong but then I though "Maybe its just an accident?", even though it couldn't have been because he was holding me appropriately before. Then he tries to stick his hands down my shorts/underwear, I jump off and sit down on my coach. I didnt really realized what happenend, but I remember he kept asking me if I wanted another ride and I kept saying no. I'm 15 now and I still think about it to this day, like I understand it wasnt rape but I still feel uncomfortable but it. I sometimes have dreams where I get sexually assaulted but never by him, also I really wish I didnt, but I kinda like the thought of being sexually assaulted? Do I need help?