M.R.
I would call and talk to a the doctor's nurse and get advise from her/him to see if they believe you should bring in your son. Most of the water from his body probably released itself in the vomit and diarrhea, therefore, he did not need to urinate...he sounds a bit like he might be dehydrated if he is wanting to nurse more that usual. Try giving him the Pedialite (spelling), in a bottle, they have them in ice pops now too...those should always be on hand at this age. It is a great sign for him not to have a fever, THOSE fevers are the worst! Good Luck!