Linda, when I was in still relatively early days of mercury detox and trying to chelate - I had plenty of difficult and confusing times and rounds that were different from other rounds and not knowing what was often causing what.
I think it's the time inbetween when you start to notice "something" is happening or maybe improving, but it is so often replaced by yet more of the same bad symptoms, so you feel like the rug has pulled back out from under you. This seems to be the pattern of mercury detox, so it is very difficult sometimes to hang in there.
I think it is a good sign however that you have noticed some changes inbetween chelation - even if they are not long lasting, it does show something is occuring. It takes a LONG time of detoxing mercury before improvements become lengthier, better, and more stabilised, rather than sporadic and temporary. I think you're wise in watching the iodine intake, as indeed it can certainly stir up metals. And in doing so, what happens when ALA gets hold of them.....I guess we're all mostly working in the dark over some of these things and if we're not certain enough about something, it's better to play it safe.
DMSA should help chelate some of the stirred up metals from iodine out a bit more safely perhaps than ALA which goes into the brain. So if you have another one of those, you may want to finish off with DMSA instead. It seems a good one to clear mobilised mercury and seem to stablise things again.
Thanks for keeping us posted on how things are going. Let's hope for the best outcome.