It is very possible and likely even that Iodine could be a big help to you. Your symptoms as you describe them are some classic hypothyroid symptoms and since the iodized salt helped a tiny bit you might try taking more. Like in the 50-100mg range with the companion nutrients that we suggest on this Iodine forum.
all the bodies hormones need Iodine to work right.
read the iodine answers section of this forum for some of the basics. I will post my list of Iodine links again so you have them all in one place and can peruse.
and yes one filling can be enough to poison you. mercury is the second most toxic substance on the planet and it can make a mess of things. Also your vaccination had mercury in them and sometimes Mom passes mercury to baby. and of course there are other heavy metals....