For one, the cell debris that is produced with pathogen die-off in your blood is a big additional load for your liver, hence your nauseas and possibly liver related symptoms. Also there a few other reactions of your body, such as stimulation of your immune defense and a certain effects to your red blood cells. Mostly of this is positive, but Miracle-Mineral-Supplement certainly will bring along some strain to your body. It is better to allow your body to adapt slowly to Miracle-Mineral-Supplement .
And then your Amalgam fillings could be a very big issue, especially if they are still in your mouth. You are likely to carry a decent mercury load in your body. I would not be surprised if some or all of your health problems are related to this somehow. MMS is believed to oxidize mercury deposits and thus sets some mercury free. But MMS can probably not bind the released mercury, which ends up floating in your body. If this is correct, you should have an elevated mercury load in your blood by now. I would go for an immediate mercury blood test to verify this.
Normally one could try to compensate a smaller mercury release effected by MMS with complementary taking of NAC/ACC. However in your case you might have to consider a fairly high load of mercury to be released. I personally would not recommend to you a longer MMS cleanse with higher doses in this situation. I understand your hesitation towards the mercury cleanse, but it could be very essential to begin with. But I am sure that some others here may have more insight to the mercury issue.