Hi Bex. I think your problem is that your glutathione in liver and other stores is completely depleted. Your body has lost most of its ability to detoxify itself. Glutathione has also a connection to immune system activity, without it, your immune system is greatly weakened too. Depleted glutathione is common among people who suffer from chronic fatigue caused by pathogens.

There are many ways to increase glutathione, e.g. cystine/cysteine, sulfur foods, ALA etc. but these will all mess you up. As soon as you give something that increases glutathione to your body it will start to detox and kill pathogens. In the long term recovery, this is still something that you must do, or you will never get well again.
In this sense taking DMSA may be the best idea, to just get the mercury out without having a further impact, because your body is unable to do it.