My son is 3 year old. He began having a fever and chills on Wednesday morning. The fever can be brought down with medicine, 5ml of Tylenol and Ibuprofen. He s very tired and has decreased appetite. He will have a couple of hours were he feels OK and will eat and play like normal, but when he starts to feel bad again, he won t eat or drink, and wants to go to sleep. We haven t had to gibe much medicine Thursday or today, but he s still very tired and hasn t eaten a lot today. What could this be?