You sound like the typical chelation addict, which is how we all start out.
From my personal experience I would recommend waiting 3 to 6 months after removal then using ALA according to Cutlers protocol. IF CHELATING MAKES YOU FEEL SICK THAT MEANS YOU ARE MOVING MERCURY INTO THE BRAIN. At least thats my understanding of the process.
The body will naturally remove mercury itself in 50 percent of the people according Cutler. I would wait until the BODY LEVELS OF MERCURY ARE LOW before messing around with dmsa or dmps.
Dont eat fish,avoid aluminum in food,baking powder,deodorants,pots and pans. Aluminum makes mercury 50 times more toxic.
Detoxing the brain can take TEN YEARS if you have 40 years of toxicity. 3 to 4 years will produce good improvements.