What Causes Greenish Phelgm?

i am taking 40mg prilosec-generic for LPR (doc is not sure i have LPR but thinks i do) since taking it, i have excess throat phelgm and it gets worse immediately after eating--anything. i have been on the drug for over 2 months, and am worse than i was before taking. is it possible i do not have LPR? also some of the phelgm is green (only in the morning within 3 hours of getting up) so have just completed 20 days of antiboitics. (i have never had acid reflux in my life). and your opinion? Cheri