I've had a cold/ congestion for over 3 weeks now. not as severe as it was in the beginning but it just won't go away. should i be concerned?

Probably not: A viral upper respiratory infection (common cold) can last for several weeks. As long as symptoms are not worsening at this point, then probably don't need to worry. Sometimes a cold can be complicated by a bacterial infection, but usually symptoms worsen when that happens. If there is severe pain, fever over 101, bloody nasal drainage, or shortness of breath, then seek care. Good luck.

Probably not: If symptoms are improving and you are not developing fever or pain then likely nothing to do other than fluids, rest and decongestant. Personally I like to take some extra vitamin c too. I like the commercially made fizzy stuff!