Did you have the bloodwork done at one time for Hashimoto's? The antibodies never go away, but they do calm down from what I understand, once they have destroyed your thyroid and you are at optimal levels. The important word is optimal levels reached....TSH between .50-1.0, Free T4 mid normal range, Free T3 mid to high normal range. Then your body can start to heal and you can start eating and exercising to assist your metabolism in getting back to normal.
Hashimotos usually tested by your antibodies, and an ultrasound to be safe. If you were dx with it by a guess, I would have another blood test. If you have it it will never go away.