Causes of excessive diarrhea and severe stomach bloating 2 days in a row at night?

GI virus?: The most common cause of diarrhea is a GI virus, such as the rotovirus or others. Work hard at trying to stay hydrated. Eating some extra fiber may help, although possibly not (but shouldn't hurt). If you're not better in a week, see your doc.

Cause is unclear: Food poisoning, gastroenteritis (an bacterial or viral intestinal infection), or food intolerances are most likely. The first two often resolve within 72 hours. Lactose intolerance is triggered by eating dairy. Gluten intolerance causes symptoms when wheat and other grains are eaten. Irritable bowel syndrome is possible. See a doctor if this continues to rule out other possible serious causes.