Orgasming while jogging!!!

I was jogging one morning and coming back I felt like I was having an orgasm, its the same way I feel when I ride. Like I had to stop running because I felt like I had just been having sex, I got weak and I had sit down a little lol. When I reached home I checked my underwear it had cum and a lot too. Like wtf? Is this normal. I mean I was thinking about my bf but not sexually.