I think you are probably right. There is a very real probability of receiving an extra dose of mercury during removal which may be enough to cause your body to react. I have read a number of similar stories.
That's why chelating is so important. I recommend the Cutler Protocol. It worked well for me. Your problem should start going away in about 6 months (or, at least, that's how it worked for me). You had fewer fillings than I had, so it may not take as long for you.
Definitely, get the mercury out of your system. If your symptoms are intolerable, you might also try an anti-yeast program.