random orgasm

Cassandra
So I was out at dinner with my family tonight when my abdomen began to cramp kinda bad. Then all of a sudden, it was SO weird, I could feel my vaginal and I think uterine walls expanding and contracting on their own, as if I was having a tiny orgasm that wasn't significantly pleasurable. 
I'm also thinking that I am pregnant, as I had unprotected sex with my SO on Mother's Day and two days after that, and I think I had what looked like implantation bleeding today. 
What the heck is going on with my body? 😂