Am I getting repeated sinus, nasal and chest congestion attacks because I gave up smoking?

I have given up smoking since the onset of 2010. Till 10th of Jan or so everything seemed to be fine. But after that I have been having repeated bouts of nasal congestion, chest congestion etc related to cold. Though my resistance to chilly winds and mild winter as such is very poor, I never had nasal congestion problems. Is this because I have given up smoking?? Please help