It is possible it is allergy related, but it could be an immune reaction after your illness. There are several simple things you could do to try to ameliorate your symptoms before seeking medical advice. First, a quality, pharmaceutical grade supplement, along with grape seed extract and Resveratrol (200 mg twice a day for a week or two) should be a great start. In addition, a quality probiotic to boost your immune system's functioning may also be a good thing to try for a week or two. In addition, removing sugar from your diet is a good way to even out blood sugars, which will also assist your immune system.

After taking antibiotics, it is often a time before your natural flora returns and these steps may get you off on the right path. If those things don't work, you may want to clear the sinus passages with a neti pot for a few days - - your pharmacy can assist you with learning how to do that. I would try the nutritional route first, as the neti pot may affect your flora, also, and getting it back to normal is the goal.

If these measures don't work over the course of a month or two, a visit to your ENT doctor may be in order. But I have a strong suspicion this may give you the relief you seek.