What Causes Stomach Cramps After Sex?

Hi, my period is usually regular and this time it was 9 days late, the period I had eofre that was also a couple days late. Ive had pregnancy symptoms and took a test but it said negative. Also, about a month and a half ago the condom busted when my boyfriend and i were javing sex. Yesterday morning my period started but it was very light, laterbin the day I got terrible immobilizing cramps which has never happened to me before. I would normally get slight crps but nothing like these. They lasted for a couple of hours and them went away/ could I be pregnant??