To be honest, it sounds like you are in a really tricky situation. It's good to see that you've taken steps to rectify these issues, though.
I'm not going to go into a lengthy list of "try this". It sounds like you've tried a good number of things to eliminate this yeast infection, but it just won't budge and--to make matters worse--the dang thing is recurring for you.
I suggest reading "Candida30: Permanently Heal Your Candida Infection in 30 Days or Less". It's not a book about quick fixes; it's a book that will help you figure out what you can do that will benefit you long-term.
I wish you the best!
(P.S. You can find the book at Candida30.net if you're interested.)