That's a long time for a stomach virus--usually I'm feeling back to normal within two or three days. Are you sure it wasn't food poisoning of some sort? My dentist got e. coli from raw spinich while bike touring last year and had to cut the tour short; he ended up being sick for about a week. And when my husband got food poisoning one time he was wiped out for days--I've never seen him so violently ill before.
I hope you feel better soon!