... it's mold. There's a particular type of mold that changes in September/October causing severe allergic reactions. I used to get the same thing every year: coughing, runny nose (at times I could hold a cup under it for the constant drip), sneezing fits that lasted a good 10 minutes.

Now I get allergy shots, and I'm on Zyrtec. The combination makes it bearable.

Try the shots, and try a real antihistimine instead of Sudafed. That stuff is crap.