have you seen a naturopathic doctor? I've had troubles with candida for years, tried to self-treat and just recently started seeing an ND.
At first, she put me on iodine, as my thyroid is enlarged (goiter), plus other thyroid symptoms. But my thyroid got larger and symptoms got worse, so I've stopped the Iodine for now.
I was tested for metals (hair analysis) and have high levels for many of them. The test wasn't expensive and confirmed what the doctor suspected.
I'm difficult (sensitive) to treat so we have to go about treatment very slowly. DMSA was too powerful to treat the metals so I'm trying homeopathic treatment now and we'll re-try DMSA when I'm done with this.
My point is that we're all different and maybe seeing someone who's trained in this would help you.