Thanks for coming to HCM. Mucus production in small amount is a normal protective & moistening phenomena which keeps getting cleared constantly by cilia which are hairy structures on mucus membrane. You have mentioned that you are a teacher, which requires use of voice for long hours continuously or intermittent; this can be one cause due to constant . Other possibilities include viral upper respiratory infection
with a post-nasal drip/draining, some milk products (yogurt, cottage cheese, butter), allergies (you need to be evaluated to rule out this since you have exposure to pet, forest/plants, ?some food allergy
), deviated nasal septum
, and any small growth in that area.
You should visit ENT specialist
and get your self evaluated. Meanwhile, you should drink more fluids and do hot water gargles.
Wish you get better soon!