I suffer from a horrible case of post nasal drip and ive run out of solutions, is there a cure or other method?

k here is my story, im 16 and been suffering from PND for 14 months now. Every morning i wake up and can feel i sticky m in my throat unable to be expelled, so either after a lot of water or time being up eventually i can get it out with a forced cough like alot of it, sometimes it is yellow globs, buts most of the time it is white clear and sticky during the day. I cough at least 100 times a day and drink an unbeliavable amount of water and i think its going to kill me. Everyone around me is always pissed and no matter what i do mucous flys out when i force cough. I have been to MD and ENT even got chest xrays but it is said there is nothing they all look at me like im a hypocondriact but goddamn im practically chocking here, i hardly eatanymore cause im afraid im going to chocke and when i do i can expel partyicles (sometimes large after each swallow) i do sinus rinses, nasal gels, mucinex and all that **** but as we speak i still feel the globs. All i feel im doing is supporting these goddamn greedy doctors!!! i was thinknig maybe the problem is a Antinuclear antibody disorder(body attcks itself kinda thing) thats what blood test indicate. Maybe it is my immune system but ive been to an allergist and dont ever touch milk or dairy products now but my last thing to try is to eliminate refined sugar and coffee cause i do drink and consume alot of that, does anyone else have this ****. I feel kinda hopeless now....need help....