I think the key is here, that a lot of us have had all the traditional tests and nothing showed up. I can think back over my life now and remember times where certain foods seemed to make things worse, in a yeast infection way, like eating too much white bread. I had yeast infections starting when I was 12. I believe that I have always had a predisposition to this and the doctor’s have ruled out almost everything else that you can rule out. I was even tested at one time for MS! So scary!
I think it is a good idea though, if you can afford it, to have tests run. I congratulate you on figuring out a solution for your problem!