This could be just allergic sinusitis which is nothing but allergy of ur nose and sinuses. This could also be CSF rhinorrhea. That is brain fluid dripping through nose. I need more history.. Do you have sneezing, nose block, head ache, does the phlegm taste salty, what is the consistency.. is it like mucus or water. Female .. 5.3 ht 72kgs you fall on the obese side. Obese female constant discharge from nose - rule out CSF leak.

It may be due to allergy,weak immunity, focus on diet rich in protien like dal egg soyabean ,lots of fruits,green vegetables..medicine s ——nasal spray XYlomist 2times a day,stream inhalation with plain water,tablet fexofendine 1times a day at night for 10 days,tablet limcee 1time a day for 15 days ..

Do you have sneezing as well ? Sounds like hyperactive mucosal disease where your nasal mucosa is producing more mucin … It is advisable to go for a consultation and proper nasal endoscopic evaluation

Is it salty in taste? Is it thick, mucus like, or is it water? Are you able to sniff it back, when it comes from nose? Recurrent episodes of sneezing? Let me know about these.

You should try do steam inhalation and take tab mucinac 500mg twice daily

As it's quite long time it seems to be chronic rhinosinusitis. You better need to get your endoscopy and NCCT PNS done

It looks like allergy.visit an ENT specialist for management

Get Physical consultation done ...for better evaluation and treatment