chronic cough with mucous

I have had a chronic cough for several years and been treated for asthma, bronchitis, whooping cough, acid reflux.  Nothing has helped the cough long term.  Until recently the cough was sometimes dry, sometimes productive.  About a month ago I started having much more mucus.  Many times it gets stopped in my throat and I have to swallow it, causing a slightly upset stomach.  Sometimes I can cough it up, I have tan/light brown stringy mucus, sometimes I have clear mucus and today clear mucus with some white spots in it.  I have been coughing so much that last night I threw up all I had eaten a few hours before.  I am having to take a cough suppressant at night to get any sleep at all.  Do you have any idea what is wrong with me and what treatment might really help?  I am so tired!  Thank you!