I also have Hashimoto's. The doctor found it when I had to have a nodule on my thyroid removed. He took the whole right lobe, so I'm going on half a thyroid gland. I never knew I had the disorder.
It's been no fun getting my levels back to normal since the surgery, either. You kind of have to sneak up on it, and you have to have your levels tested every three months or so, and have the medication levels adjusted accordingly. So far, I've only had my meds increased, not decreased. I'm betting I could take 200 mcg of the stuff every day and that wouldn't be enough. I think I need more of the hormone than most people do, or something. I don't know. I know it's frustrating.