For a while now, I have been lactose intolerant; but i still eat dairy almost daily, and it usually just causes me to have diarrhea. More recently, every time I eat something(especially a large meal) I get terrible stomach pains. also, I used to be able to drink quite a bit of alcohol, and have nothing happen.. but now if I even have one or two drinks, my stomach is in such severe pain, I can't drink. Could this be a stomach ulcer?