Last week I was with a guy on the last day of my period. He accidentally came in me. Now I’m having severe back pain that feels like a period cramp. I have never had this outside of my period before, I was wondering if it could be implantation even though I haven’t ovulated yet. I am supposed to ovulate in 11 days. No signs of bleeding yet. I looked it up and it said implantation cramping is usually mild and accompanied by bleeding, also that it happens after ovulation usually before the missed period. Help?