When you first come down with the flu you will usually begin getting body aches and a fever which usually lasts for around 3 to 5 days.
Then you will feel tired and fatigued and that tiredness and fatigue can linger and last as long as 1 to 2 weeks.
So you might stop feeling tired within a week or you might still feel tired and drained down of energy for 2 weeks.
Most times when I have the flu I have the body aches and fever for 4 days and then after that tiredness and fatigue lasts another 5 days before I start feeling energized again.
The flu should be fully over within 2 weeks which is 14 days but if not and it seems to get worse or you think you're developing pneumonia then go to the emergency room.
If you or someone who has the flu will not get any fluids down them and they become dehydrated you need to get them to the hospital so they can introduce fluids through an IV.
The flu can be deadly especially if the person is elderly, has a weakened immune system or is younger.