What pill will balance out my stomach?!?!

Zinc supplements can stop diarrhea, but you should try to figure out what is causing your problem and not just treat the symptoms. From the sound of it, you might have some sort of food intolerance or allergy. I would recommend doing an elimination diet where you avoid eating one type of food for an entire day and see if you feel better. For example, don't eat tomatoes for a day and if you feel better, then you know you have a tomato allergy. If you don't feel better, try a different type of food. Most food allergies or intolerances are caused by dairy, soy, wheat, shellfish, nuts or tomatoes so you might want to start with those.