How should I deal with diarrhea and cramps?

See your doctor. If this is a chronic problem you should see your doctor. For acute, non-bloody, diarrheaplenty of fluids, Imodium (loperamide) or kaopectate are appropriate. If no improvementin 2-3 days see your doctor. For bloody diarrhea or for fever see your doctor.
Clear liquid. Diet until the diarrhea slows down then slowly advance diet by adding bananas rice apples vet 24 hours and going back to normal diet if diarrhea does not return. Remember to replace fluids lost through diarrhea with increased oral liquids to the extent possible. If not improving or if worsening please seek medical attention.