What could chronic wet cough in 24yo non-smoker be?

[Lyn1992]

I remember seeing the doctor for my cough about 5 years ago. At the time she said it was exercise induced asthma, but the inhalers never worker. I had pneumonia at 19. I did not seek additional medical attention for my cough until recently, because besides the mucus I didn't have any other issues. Now that I have been doing research I have scared myself into thinking I have cystic fibrosis. I saw the pulmonologist 9 months ago. I had clear x-rays and a normal spirometry test results. I was also living in a house that had mold, she ran blood tests and there was no mold in my blood. I did have a bilirubin level of 1.4 and normal levels go to 1.2. She diagnosed me with sinusitus and rinitus and told me to take nose spray and clairtin. After my appointment with her I felt relieved. I did take the medicine for a while, but stopped when my cough cleared up. I got sick over christmas and my cough lasted about a month and I just had a sinus infection about 3 weeks ago and I'm still having a wet cough  (clear mucus) with wheezing. I also cough up clear white string/worm shaped things sometimes.

What do you think it could be? cystic fibrosis?