Cramping after sex

Okay so I just had sex with this guy who has a larger penis than I am used to. During sex I didn't really experience any pain besides him going in too deep. Lol sorry for the tmi. Anyways about 10 minutes after sex I started having insane cramps in my abdomen area and felt extremely uncomfortable to sit down. A couple of hours later my cramps aren't as severe but still hurt. Does anyone know why this could be?