My Grandson is 3 years old. He came home on Friday with a runny nose and that led to a cough and a slight fever. He had a Flu shot 2 weeks ago, could this be the flu or is it just a cold. Today is the Full 3rd day of this and that cough is awful. He ate great Saturday and Sunday, but wouldn t eat very much at all today, just a yogurt, 1 cheese sandwich and some applesauce and that worries me, at what point should I take him to the ER or to visit his Dr.?