Probably from those grapes you ate from McDonald's ! Probably just a little stomach flu or something minor. Take a couple of Alka-Seltzers. They always help.
I have EXTREME discomfort in the stomach here. So am I sick?
Not necessarily. It could just be gas, or constipation. If you are running a fever as well, then I would be more concerned.
Go eat some grass ... Like any sick dog does.