Why do i have bad cramps and poop/diarrhea on my period? how can i make it GO AWAY!!!??? (10pts)?

i am 14 and i get really bad cramps for just a little while before my period. then i will have diarrhea and itll last a few days then it will just happen just each morrning and wake me up. its gross. i can barely make it to the bathroom. now iv had it since wed and i am getting poops like crazy! what can i do to help??? please! thx