You said when you drank water you felt better, could you be dehydrated? I've recently been experiencing a lot of stomach aches and nausea and I think it's from new medication but I don't know for sure. Not eating though will probably only make you feel worse. Eat, and drink lots of fluids and try to just relax and take it easy. That made me feel a lot better. You could also try something like some pepto bismol. I'm sure it has everything to with you being tense and stressed and not eating.