Yeast Infection Help

So I have been to numerous doctors and gynocologists about this problem but they all say the same thing. That i have a healthy vagina and what not. But this is obviously a yeast infection that wont go away no matter what. Its white and smells bad and my labia is red and sore. I have had prescription meds for it but none are working. Could anyone suggest ways to help get rid of the stubborn infections that have been with me for 2 years?