am i making a big deal out of this?

so i was hanging out with my ex (we were friends after we broke up) and we were with a group of friends. we were at a festival type event. we all went back to one of our friends truck and i remember he pulled me away from the group to the other side of the truck (no one could see us). i remember he went in for a hug and than started grabbing my butt and touching me in places that were inappropriate. i was trying to pull away but he kept holding on. he finally let go and i just walked away. it scares me honestly because i trusted him. maybe im making a big deal out of this but when i think about it, it just gives me anxiety.