Glutathione contains a single thiol. Single thiols grab mercury weakly and move it around without really helping to eliminate it. The moving mercury gets redistributed to new locations making the person sicker.
I can't speak to the toxicity of mercury, or how glutathione interacts with it, but I do know that glutathione will generate γ-glutamyl amino acid or glutamate, which is pretty much the last thing you need right now, given what appears to be your systemic issue with GABA/glutamate balance right now.
Remember, one thing at a time. It makes it easier to figure out what's working for you, whether you need more or less of it, or if you might need something else entirely.