What Rapunzel said.
I like that quote there from Tony Attwood, I find that still works for me in adulthood. I can be very happy on my own (not all the time, but most of the time) though as soon as I have to interact with others again I instantly go back to being stressed out, confused, and upset.
Like both of you, I hated P.E. at school. It was the most pointless class ever, and most days I either skipped it or got a letter from my mum to excuse me so I could spend the two hours reading or doing work for other classes. I sucked at sport of all kinds really, with the exception of swimming which I was really good at and even participated in a few galas. Though I enjoyed it, I didn't enjoy the galas so much because of all the other people there. I prefer to just be in the water alone with my thoughts whilst I swim.