Wow, I'd think that's exciting and scary all at once! But if it helps improve your health, then it's worth it.
One thing I'd ask about, since they're taking out the whole thyroid, is their success at preserving the parathyroids (there are 4 parathyroid glands sort of stuck on the back of the thyroid, and they're responsible for calcium metabolism). Ideally they keep the parathyroids intact w/ their blood supply, but sometimes they have to transplant the parathyroids into the local muscle to regain blood supply, which is usually very successful at maintaining function. Interesting stuff.
Whoops, sorry, there's the doctor in me sneaking out ;-o
Lots and lots of healing vibes to you!!!