So.... For 15 years you have had no mucas problem. Man have you been lucky.
Starting from day 1, I have had a mucas problem.
But I can minimize it if I drink plenty of fluids and cranberry juice.
Maybe you are like me. I find that, at times, I don't drink as much water as I should because I am afraid of night time incontinence and I dehydrate a bit.
But I envy you the 15 years!
I hope the solution is simple as this and you can again be a shining example for all of us here.
Best of luck to you. I hope this is not a sign of any other health issues.
George