Diarrhea, vomiting, really bad stomach ache?

Put some ointment on your backside to protect the burning tissues. Drink lots of water so that you won't become dehydrated. it may just be a bug, can try some antidiarrheal available over the counter. Go with clear liquids for 24 hrs to give gut a rest, no milk or dairy, no orange juice as this will contribute to burning. Go with Gatorade, water, 7-up, herbal tea, and dry toast and crackers. After 24 hrs, gradually introduce a little soup and other light and bland until you are sure it isn't going to be disrupted.