Post Sinus Surgery with unilateral stuffiness

I was diagnosed with nasal polyps 1 year ago and had them removed in September 2008. Prior to the surgery I was experiencing pressure and stuffiness generally on my right side. In a CAT scan, it reveled that my right sinuses were completely filled with polyps and a small polyp was growing on the left as well. The surgeon removed all the polyps and basically did a right endoscopic frontal sinusotomy, right endoscopic ethmoidectomy and bilateral endoscopic maxillary antrostomy with tissue removal. I had hopes that this would relieve the stuffiness that I was experiencing on my right side, but now 2 months later it is still stuffy. There are periods of the day where it is not stuffy, but generally  I wake up with it very stuffy and definitely go to bed with it stuffy. I am on flonase twice a day and was suggested to try to Astelin to alleviate the problem. The surgeon did take a look about 1 week ago and said that everything still looked clear. I also had some allergy test done and it was concluded that I have a dust mite allergy. I have taken all the suggested steps given to try to  lessen this allergy. I am sort of at loss at what could be the problem? Any suggestions? Also, I have never experienced consistent unilateral stuffiness until two years ago. I am 33 and have been diagnosed with low thyroid. I am taking the recommended dose. Thanks for any help.