I Believe I Have a Nicotine Allergy

I started smoking around six months ago.  I started with a couple a day and then started smoking more.  Within a month, I had started smoking half a pack or even a whole pack a day.  That's when I started waking up in the middle of the night coughing my lungs up and spitting up thick flem (phlegm).  And sometimes, even throwing up due to the coughing.  This continued for about a month, then I started taking decongestants and it got a little better.  Because of this, I thought that it may have just been a cold or flu.  But as soon as I stopped taking the decongestants, the coughing came back.  I have recently started looking into the possibility of a nicotine allergy, and I was wondering if anyone else has had this problem or similar.  Or maybe even if someone has some actual information that they could share, it would be incredibly useful.  And, before you ask, yes I'm quitting cigarettes, but I just quit, so I haven't seen any change.

[bsmsl]

I would say that you had developed the smokers cough.  The polution from smoking causes inflammation which produces mucous which must be coughed up.  

Good choice on quitting while the habit was young.  Things will improve once the inflammation has had a chance to heal.