Stomach cramps

Did a 7 km Street-O run last night. I knew I'd either float or struggle after the orienteering last week, but what I didn't expect was STOMACH CRAMPS. What gives??? I'd had a couple of dry biscuits a couple of hours beforehand, and a large handful of strawberries, grapes, and a plum earlier in the afternoon... hmmm... perhaps that was it. Whatever it was made the run very unpleasant, sort of like a menstrual cramp (sorry guys) where you want to curl over to stop the pain. It lasted maybe 15-20 minutes in the first half of the run. Horrible - hope that never happens again.