I have a weak stomach, in the sense that every time I have new

If you're eating healthy, and I mean no unnecessary sugars plus some forms of exercise, and you should have diarrhea, you might want to talk to a doctor. You might have some infection/something wrong with your intestines.

Some people have a more sensitive stomach and can feel very fast if something is not healthy for them especially if you are not accustomed with the food or if the food has started to go bad. Same like >16907921 I advise you to see a doctor but try to see a doctor that will prescribe you a natural remedy.