Women PLEASE answer!!i have shooting pains between my and rectum?

i usually get this weird pain before my period or during it which i heard its normal but i just got my period on the 17th so i dont know why i got this pain during . when he went deep inside i felt this shooting pain.is this normal??i took the morning after pill and got my period three days late and lasted only 3 days.am i suppose to have another period again??why am i feeling this pain now?