My son is 7 years old and started throwing up Thursday at about noon. We had to take him in because everything we tried giving him he threw up. He was released form hospital on Saturday around 12. He has now developed a rash on his stomach, back and mid section. It is itchy and red and a little splotchy. He is running a low grade fever and still does not want to to eat. We have been keeping him hydrated and the only thing he will eat is yogurt. He is sleeping a lot. What could be going on?