There is scientific evidence that the TSH is suppressed for almost a full day after a significant dose of
thyroid med, so that does not usually indicate an
overdose. You can tell by Free T4 and Free T3 levels.
Hypo patients are also frequently deficient in Vitamin D, B12 and ferritin, so you should make sure to always get those tested and supplement as needed to optimize. D should be at least 50 ng/mL, B12 in the upper part of its range, and ferritin should be at least 100.