Don't take this lightly! I have a theory. There seems to be something going around the country and it seems to be harder on those who have other problems. It doesn't make one feel "sick" per se, it just won't go away and can set up in the lungs causing breathing problems.
My wife and I both had it. I normally don't get sick/get well quickly. It took me a month to kick it. I never felt sick (no fever/usual cold symptoms), just unusually "snotty". After two months my wife finally went to the doctor. She also didn't feel "sick" but couldn't get a "good breath". The doc gave her a breathing treatment, an inhaler, and antibiotics, which are helping. She doesn't suffer from allergies, nor do I. The doc also said that "it" was on the verge of turning into pneumonia in my wife's case.
The "usual suspects" (allergies/hay fever/pollen count) seem to mask this thing and make people dismiss it as something else. Don't be fooled! If you have allergies, they may be making this "stuff" worse, but it's not JUST your allergies/hay fever. Go to the doctor and get checked if you can't shake it after a few weeks. What can it hurt to get checked out?
You may think I'm nuts but I believe that something is going around and it's not being run down by the docs because it isn't something that acts quickly on people or can be easily diagnosed (like the flu). My son came in to visit from Maryland and he had the same symptoms (not sick just "snotty" and coughing, took forever to kick it). Whatever "this" is, it's not local and it's more than hay fever.
OK, I'm done. You can call me Mr. tinfoil hat now!!