every few months or so about a week before my period i’ll wake up with the worst possible pain in my right abdomen, and my stomach is swollen like a ballon. it keeps me up all night and lasts the next day, and leaves my stomach sore for the next couple days. it’s been happening to me since i was around 11 even before i had gotten my period, i’m 16 now. anyone had something similar, or knows what it may be?