I Have Nasal And Sinus Congestion, Some Post Nasal Drip,

I have nasal and sinus congestion, some post nasal drip, a feeling of lightheadedness, and ear ringing for about three months now. Sometimes I get a mild headache and dizziness but otherwise quite functional. Appetite seems fine, and not fatigued. My GP did a full physical on me, including a sinus X-ray, and everything seems fine. He has prescribed Nasonex, which doesn't seem to be helping much. I have bee referred to an ENT specialist but can't see him until January 2017. It is hard to enjoy daily life and work feeling this way. Is there anything else I can do or should be thinking about? I am very anxious that it could be something very serious.