Should I Stay or Should I go Now

My son Troy came home from school yesterday in what seemed to be a fog. He had a fever and the bus driver said he actually fell asleep at school and slept all the way home (13 miles). When I got him inside he fell back asleep on the couch and didn't move until about 7 in the evening when he got up to run to the bathroom. He almost made it :( He threw up right in front of the toilet,poor kid. He threw up one more time last night and then he was able to keep some children's Advil down. After he took the medicine he seemed to perk up a bit. Even this morning he was back to his normal bubbly self. However at around 12 he used the bathroom and then said "bath please." That's code for "I made a present in the toilet please flush it and give me a bath." He played for a bit and then got out by himself and sat by his brothers while they watched "River Monsters" on TV.  This was while I was making lunch (taco salad). Towards the end of cooking I noticed the house was really quiet. I thought Troy must have fallen asleep on my bed.When I checked he wasn't there so I looked in his room and sure enough he was asleep on his bed or so I thought. I reached over to feel his head (which was fairly warm). Apparently just that gentle touch was enough to wake him or he wasn't totally asleep yet. Anyways he came out from his room and laid on the couch and has been asleep there ever since. This is not like him at all. The last time he had the flu he would throw up and then run around and yell  and bounce on his bed etc. Whatever this is has him knocked down for the count. If it doesn't let up by the evening I'll be taking him to see a doctor or emergency room if it get's any worse. I know it sounds funny but something just doesn't feel right about this. My mommy intuition is tingling so to speak.