Stomach pains in a 2.5 year old

My child Jordan he is 2.5 years old, when he was born he had a hernia under his belly button, about a month ago he caught a realy bad virus, as the hospital called, he was throwing up everything including water, had diahrrea for about a week, did not want anything to eat, and complained about his tummy for over 4 hours on january 11th, we took him to our children hospital and they had told us not to worry in regards to his hernia, in November of 2007 he was in for ultrasound, and we weretold it is minimizing, now in the past 2 days he started complaining for tummy pains again does not want to eat too much either, what can i do?please help us