I have been dealing with this for years. One doctor told me I probably have some kind of blockage. I don't have health insurance so I can't get an MRI done to see what is wrong. I spend a ton of money on antihistamines and decongestants. If I don't take Nyquil at night, I wake up with a severe sinus headache.
I am constantly clearing my throat or harking and spitting. I am so tired of it!
Someday maybe I'll get insurance and get the problem fixed.
I have had several sinus infections in my life. Mine are mainly due to large abnoids which cause me to sleep with my mouth WIDE open. From personal experiences I have learned if you have any color in the drainage then it's easiest to go ahead and get some antibiotics to clear up the infection. I have always found it helpful to take a nasal decongestant while taking the antibiotics to keep it all flowing and get that junk out of there. Then once the infection is gone and it's all clear again take an antihistamine to slow the faucet you opened with the nasal decongestant. I use Sudafed gels (actually the equate walmart brand). The gels aren't used to make meth so you don't have to go through the paperwork to get it and it doesn't give me the jitters like the lil red meth making pills. Then I use benadryl(again walmart brand....why pay full price for a name when it's the same thing) to dry it up. I think the chances are you didnt take a long enough dose of antibiotics the first go around to completely get rid of it...HOPE this helps. Of course you doctor should be able to help.
that is really gross!!! fluids fluids fluids...and it sounds like you may need to go back to the drs...maybe for an antibiotic?!! also, i know you said you dont have allergies but there is a new allergy forum on here that may be helpful too!! good luck!!