Hi, This Might Be Coincidence But I've Started To Notice

Hi, this might be coincidence but I've started to notice that I get severe abdominal contraction like pain a week before my period sometimes a day before my period. It is followed by vomiting and sometimes diarrhea. Only lasts a day and adter vomitting i usially feel better enough to sleep it off. I've never had menstrual cramps. If this is what it is then I'm sorry I'm asking. But I'm worried it might be something more.