I had flu with a fever for 13.5 days, fever went 2 days ago and other symptoms are disappearing also, how long should i expect the fatigue to last?

Please be patient: Hard to say - may require another 2-4 weeks to return to "100%" with noticeable improvement each week. A condition known as post viral fatigue, where over half may be ill for 3-6 months or more, occurs equally in men and women, & is associated with specific viruses. Chronic fatigue syndrome is diagnosed if fatigue persists after 6 months. Stay w/in your limits; conserve your energy while healing.