Still have stuffy/runny nose

So i got sick with a cold and cough about a month and a half ago, and i still have congestion and a runny nose sometimes. i take sudafed and another presciption drug that i got from my doc for the congestion but it's not going away. i work at a restaurant so my hands are always clean, why am i still have cold symptoms?

[BradyAm]

and i also sometimes get sore throats that range to last a few hours to a day.