help!

On sept 8th my bf put the tip in but it hurted so bad(I was a virgin) so he stopped. the second day he went in fully it hurt so bad! He didn't use protection but didn't ejaculate. Now I've been getting bad cramps and it feels like I'm on my period but when I check there's nothing there just vaginal discharge. After 2 days I saw light blood stain on my undie and thought it was my period but wasn't. Today I'm experiencing very bad cramps. What can it be?