i cant stop coughing

Help me please. I've been sick for 4 months.  I've had this dry cough for about 4 months.  It started with bronchitis.  I had it for 3 weeks and every week I'd go back to the doctor and they'd put me on different antibiotics or steriods.  On my 4th trip to the doctors office they said I had pneumonia.  So i did steroids again and more antibiotics and an inhaler.  Two weeks later I still had the cough and they told me bronchial spazms and yet again more steroids.  Two more weeks and back to the doctor he told me that im getting sick so often because of my allergies so he prescribed me allegra-D 24 hour. I've been to the doctors office 12 times in the past 4 months.  I just changed doctors and thought maybe this one got it right.  She said I now have asthma.  So I'm taking advair 2 times a day and im supposed to use the inhaler (xopenex HFA) when i have attacks.  I use it sometimes it helps but mostly it doesnt.  I have a constant tickle in the back of my throat or even lower than that I'm coughing so hard I'm throwing up, my entire body is sore, and I can't sleep.  Somebody please tell me what's wrong with me?