Hi,I Have A Flu That Wont Go Away....i Have Tried

Hi,I have a flu that wont go away....i have tried using anti histamines and a nasal spray that I was given in the hospital but there is no improvement....my nose gets blocked at night and I cant breath...during the day I usually hv a runny nose n I sneeze all through despite using the antihistamines....kindly advice me on what I should do.