Stomach ache after eating anything, largge or small. Thirsty. What is wrong? Drinking water and tea and taking Tums (calcium carbonate)

Depends. This can be a GI infection, gallbladder problem, ulcer, reflux, or something more sinister: such as low blood flow to the stomach or heart attack. It depends on your age and history. See a doctor. You may need an ultrasound or egd.