81 y.o., otherwise healthy. Working on my PC and, all of a sudden, I began to have abdominal cramps. Became severe but subsided after 2-3 hours. Now I am tired. No fever, no vomiting, diarrhea, constipation, bloody stool, blurred vision; no nada. What might have caused the cramps? Food poisoning unlikely. I am very tired after this experience.