You may have headache, fever, chills, aching muscles all over, lack of appetite, sore throat, nasal discharge, dry cough, weakness, and pain or burning in your eyes. That's the flu.
Flu is caused by a virus.
It usually goes away by it self. Sometimes, complications develop such as bronchitis, sinus or ear infections, or pneumonia. Complications are serious for the elderly and for people who have chronic diseases like diabetes and heart disease. REST - go to bed and stay there until the fever has been gone at least 24 hours. Bed rest is very important.