You eat sushi? (Gasp!) Take the pledge! Take the pledge to never eat it again, child. You should read what JessesMom experienced because of sushi.
That was an interesting thought about the adrenals and thyroid. I have been diagnosed with being low on both. Blood tests, at least initially with the thyroid, failed to reveal the problems. A urine test showed it on the adrenals, but you have to find a doctor who is willing to do a urine test.
I found the stopthethyroidmadness.com website to be fantastic.
Here is my own story with parasites & mercury in the link below, in case it might be helpful. By the way, I tend to have the same shakiness & fatigue from die off - plus other symptoms. It does go away eventually.