My biggest problem was fever. After a couple of days at 102, I went to see the doc, and he said "Yup. Lots of this going around this year. Will be two weeks before it's back to normal. Fluids, bed rest, etc etc etc". When I told him that I needed to get back to work, he just laughed.
Doc was a pretty sharp guy. Sure enough, the fever broke exactly two weeks after symptoms started to present, though I was weak as a kitten for another 2-3 weeks.
Never again, I hope.
At first sign, take Tamiflu