How do I know if I have the flu?

If you have flu, your really sick. And I mean sick.. Body & headaches. High temp. No energy, dry throat, cough, nasal, nausea, vomiting, diarrhea, congestion of lungs. Flu is a viral upper respiratory illness. Some times people with flu then get pneumonia . With flu your sick for weeks ! Your so weak & uncomfortable you don't want to eat or do anything...... A Lot of times people think they have flu, when it's a tummy or bad cold virus. once you've had the flu you will know the difference... It's a serious infection. And the 5th leading cause death in the very young & over 65 age group. Hope you don't have flu,& your friends are well !