This is an uncomfortable topic to post because it isn't very pleasant to talk about. But, I feel I must share because someone may have the same symptom and this could help.
Occasionally I had diarrhea that was violent. The timing was always about 2:30am. I would be awaked by painful cramps. My legs shook turbulently and sweat weeped down my forehead. After the exhausting elimination, I felt so much better. I just thought that I had eaten too much. I never suspected gluten. This went on for 35 years.
The summer of 2012, a few months before I tested positive for gluten intolerance, I was the sickest I've ever been. I was stuck in the bathroom with vomit and diarrhea for over 3 hours. I couldn't stop and started to vomit blood. I felt something was terribly wrong. I thought I was going to die. We called the paramedics because I couldn't leave the bathroom to go to the emergency room. Strangely, I didn't have a fever and couldn't keep down the anti nausea medication given to me. Six hours later I was fine and only weak. I know that it was my body's reaction to gluten. It wasn't food poisoning because no one else in the family was sick.
It has been a full year now without gluten and, no surprise here, no more diarrhea. I still marvel. I never thought of myself as having intestinal issues because the diarrhea was only every few months or so. I wasn't the normal specimen. In fact, most people have varied symptoms.
Let's keep sharing.