Have you thought about being allergy tested? I have a decent asthma component to my CF and allergy shots have really helped me and I am also on Advair, Singulair, Allegra, Flonase, and Prednisone sometimes. I notice them helping the most when I'm sick and not wheezy or getting short of breath from doing my nebs. Might be something that could help you.
Good luck.
Good luck.