Does anyone has any thoughts on a long lasting cough?

[kmasco]

I started to have a nagging cough about three weeks ago. It got much worse at night when I tried to go to sleep. It would take me hours to finally get the cough to subside long enough to go to sleep, but then I would end up waking up three or four times a night coughing. It would keep waking my husband up too. It is a very deep dry cough and has caused me to gag several times. I finally went to see my PCP and he prescribed Azithromycin and Bromfed. I took them until they were finished and neither one of them helped. I am now on Prednisone, an inhaler and Levofloxacin. The cough has subsided some, but it is still there. It is a non-productive cough and there are no other symptoms except some tightness in my chest. My PCP referred me to a pulmonary doctor. I have a pulmonary function test on the 15th and then my appointment on the 23rd. I am kind of nervous because I am a smoker and have been for over 20 years. My co-workers swore it was whooping cough, but I do not really have any of the symptoms other than the coughing.  

Has anyone else experienced this type of cough?