I've suffered with Candida for 3 years since having 10 weeks of Antibiotics and realising I had mercury poisoning too. I've tried everything for the brain fog but nothing seemed to fix it - along with my chronic fatigue. Have a look through some of my old posts on here, you'll see! :(
I found out that my methylation needed sorting first (to help the liver work properly and eject toxins properly) but also I found out about Hyperbaric Oxygen Therapy. During my first session I was yawning like crazy. My body was literally gasping for oxygen, and by the second session my brain fog lifted and so did my energy. It was amazing!!!
I find that one a week is good but can be quite expensive so I decided to open a Hyperbaric Clinic near me (in London) with a well known Hyperbaric Doctor. To see how HBOT works see here: http://hyperbaricoxygentherapy.co.uk/about-hbot/ it has a good video and there is also a good page about cancer too.