Suggest Treatment For Nasal Congestion And Throat Irritation

Hi, For a couple months I ve had nasal congestion & throat irritation (post nasal drip?) and cough a lot to clear my throat (about 50% productive with clear mucous) , and on occasions have thick yellow / green nasal discharge, and nights with significant sweating. Went to P.A. about a month ago, discussed and started Zyrtec (Costco brand) treatment for allergies (tested in past and high reaction to grasses etc) and cough medicine. Within a couple days started heavy nasal discharge (thick yellow / green / minor blood mixed in) and was feeling better breathing....but symptoms are back as bad if not worse, have stayed w/ Zyrtec, but minimal cough medicine. Planning to go back to P.A. next week,any advice? p.s. I had past history of sinus infections / sinusitis and in most cases after a few weeks I d get a couple nights of really heavy sweats and flood gates would open with very heavy thick discharge and I d be back to normal.....just can t seem to get to that point now!