Healing Vibes needed

Wow - R's flu seems to be taking on evil death flu proportions. He actually seemed to be improving for a while today, and even went out with our friends for a quick bite to eat. He crashed hard after that and his fever jacked up to 103. Right now he seems to be sleeping pretty well, I'm just worried about when to take him to the (expensive) clinic or to encourage him to just ride it out. It seems like the flu - fever, aches, tummyache and diahrrea - but I'm worried that it could be a parasite or meningitis or some equally wierd and evil thing that sometimes surfaces around here. The funny thing is that we are trying to figure out anything that we ate differently in the last 4-5 days and can't come up with anything. I'm thinking that might rule out the parasite thing.

Anyone with advice - please comment :)