I Am A 35 Year Old Female. I Have Doctor

I am a 35 year old female. I have doctor diagnosed seasonal allergies. My most bothersome symptom is coughing due to postnasal drip. I have gotten some relief from the OTC dosages of Allegra, Claritin and Zyrtec but I still have post-nasal drip and cough. I'd love to have some real relief! What medication would you recommend? I'm going to see my doctor but I would like to know what others have to say. Thanks!