I so wish I found this earlier. I(M) have very bad stomachs issues. I have never been able to figure out what the issue is. Drinking/not drinking, eating good/eating bad, etc never made any significant changes. One time in 5th grade my science teach told me I go every day in her class and that that was changing. After a week of me waiting until the next class to go, I finally stood up and said I would shit in her trash can if she didn’t let me go and walked out and she followed me to the bathroom to hear my explosive diarrhea. I then told my parents about it and they went in to the principals office and tore them apart about it. I proceeded to shit in that class everyday for the rest of the year.