Its been 6 weeks since getting the flu. why do i still have a bad cough?

Post viral cough: What you have is probably a post viral cough. This occurs when the flu or other respiratory infection causes inflammation in the airways. It can take 8-12 weeks to resolve. The best that you can do is treat it symptomatically with cough medicines, throat lozenges and staying hydrated. I hope it leaves you soon. If you develop fever or other symptoms see your doctor.