For the last thirteen years i have times when i have not had a bowel movement for over a week then suddenly i have to rush to the loo with a forceful diarrhea accompanied by the shakes cold but tremendous sweating cramps feel like vomiting (sometimes actually have simultaneously) need to hold onto something caise i feel like i am going to collapse or faint. once it is all over i feek ok but exhaused. the first time it happened i thought i was dying. can anyone tell me what it is why it only happens say six to twelve times a year and how to prevent it happening?