I've read through the whole thread, and my situation exactly matches several already posted.
I had Omicron in Sept 22. I was treated with ivermectin, and it actually worked quite well, I thought. The case was fairly mild anyway, like a typical cold but with a more severe sore throat. My vax status was the two main doses plus a booster, all in 2021.

Ever since the Covid, I've had a lot of post nasal drip and mucus in the throat. I have a lot of seasonal allergies so I figured it was just allergies. Then after being outdoors for most of the day on a cold December day, I came down with what I assumed was a cold. It started with massive post nasal drip or drainage, which gave me a harsh sore throat. I treated it as a cold, and it took about 4 weeks to resolve. I had a lot of sinus congestion for an additional 4 weeks or so.

I went to Florida for a week's vacation in February. We stayed in a musty condo but I felt better than I had in Texas. (Humidity helping, or just different allergens?) Upon return home I had the same crap again. And on the 20th of February, after being outside for hours on a warm, very high pollen day, I had the same "cold" show up again in the same way. Tremendous drainage, very sore throat, etc. The post nasal drip had been happening all along, but this day it went into overdrive. Now I am 7 days into this event, with very little progress. Also, my tinnitus is a bit worse than normal.

I take antihistamines, Flonase, and do a nasal rinse twice a day. Every evening it gets real bad. Based on something posted earlier, I am going to try to avoid anything at supper that would have sugar. If it helps I will report back. Also, I have 9 days worth of ivermectin left over, and I am going to try it. It is extremely safe, so it's worth a try. It sure seemed to help when I took it for Covid.

It's getting close to bedtime and I feel like I'm drowning in this crap. It sounds like it is not worth making a doctor appointment, but I probably should.