Oh Sugar! Let's see, is he bloated at all? Did you put your ear to his belly and listen for awhile (you might be able to hear quite a bit going on in there)? Did he poo okay today?
Do you have any pepto on hand? I'd give a good 1/2 tsp right away, then another in an hour if he is still in stress. Are his gums okay, pink and everything? And he was still hungry this a.m.?
Oh, you could also give him some soda crackers if you think his belly is upset, along w/ pepto.