I don't like physical contact?

Okay, well, I don't know where to start. Since I was young, I never liked physical contact with people I'll gladly go up to a stranger and hug them, or my friends, but the minute I think about that hug, or think about how my friend is laying on me, I either get anxiety (to the point of throwing up sometimes), or uncomfortable. With my parents whenever they try to put their arm around me or hug me, I just get uncomfortable and move away. I'll hug family members if they want to, but I just kinda turn it off in my head. When I like a certain person more than a friend, I get really bad anxiety, whenever they would cuddle with me (as friends even, but I liked them more) I feel like I have to throw up, and so I end up leaving and going to their bathroom. I don't know why, it mostly started that I can remember when I was in 8th grade, I am 17 almost 18 now. I just want this feeling to go away but I feel like I'll always have this weird feeling with me. Trust issues? I don't know.