I've been suffering from largely the same issues. I've been taking 100mg Iodine for about 2 weeks now... I do believe it's an improvement but I don't think it's the silver bullet I've been looking for as I still suffer from massive fatigue (it has in large part fixed my digestion though... it has been incredible in that regard)
Me personally, I think my fatigue / brain fog issues will most likely be solved with Colloidal Silver and B12 injections.
I've been a vegetarian a good majority of my life (though it can affect meat eaters) and b12 is a common deficiency in people that are fatigued. A lot of people have recommended Colloidal Silver in this chat and I've read that it can positively affect absorption of b12, along with fixing a host of other problems: http://www.thesilveredge.com/depression.shtml
I definitely recommend to start the Iodine protocol and then consider taking (or making) good Colloidal Silver (make sure it's the right kind), and B12 if your body needs it.