I came down with the flu about a month ago, and had to skip 7 work days.
It really sucks.
Just stay in bed and drink a lot of water.
And as soon as you're able to, take some walks outside and get some fresh air.
Get well soon buddy.
PS: If you begin to cough a lot, you might be getting into the first stages of pneumoni too, which I also got. Then you need to see a doctor and get perscribed some penicillin of some sort.