How to get rid of post nasal drip ?

I ride horses and have horrible allergies all year just from being outside and probably breathing in allergens and hay particles. The post nasal drip and cough are persistent. I use a humidifier all night, take Zyrtec before bed and Flonase. I try to sleep sitting up and right now I have to have multiple Cough drops to stop coughing while sitting in bed. I even started using a nettipot. My eyes get crusty and goopy too and it can be really hard to sleep at night. I’ve already been to the doctor twice and they just tell me to take the Zyrtec and Flonase. I don’t want to give up riding, is there anything I can do? This has gone on for most of the last two years. 

2021-01-14T06:35:42Z

Also I was on antibiotics a month ago because I had pneumonia and that was the only time in a long time I felt better almost completely in my sinuses. Is it possible I constantly keep giving myself an upper nasal sinus infection? Even when my nose is clear when I breath and use the Nettipot it does not come out the other side very well just a few drops at a time. So I wasn’t sure if that was because my sinuses are inflamed. 

Tavy2021-01-14T08:58:10Z

I had nasal drip and my Pharmacist gave me Nasacourt a Steroid nasal spray. Cleared it up in a week.
Pharmacists know more about drugs than Doctors.
UK