hashis can be scary, but mostly that comes from what the docs say. you can have temporary worsening of conditions. you can pulse your Iodine intake(break a day or two and get bright back to it) and you can hit the salt. selenium and boron and magnesium are important. if your thyroid is out of whack then probably so are the adrenals and liver.
perseverance will pay off. trust yourself over anyone else, including me. learn to listen to your body. if feeling like you used to wasnt healthy then you need to be feeling different, which isnt always pleasant at first.