1 year post thyroidectomy...on 125 ug levo, levels been stable. have had sudden headaches, fatigue. had tsh fri, 6.8 and 9.6 within 3 hr. pituitary?

Not pituitary: Hi. The only pituitary thing that would do that would be a TSH-secreting pituitary thyrotroph adenoma, and those are vanishingly rare. As you know, the goal for your TSH is to be suppressed, generally in the 0.05-0.10 range. I hope when your TSH was 6.8 and 9.6, your doc at least drew a thyroglobulin; if it's undetectable with the elevated TSH, that's very reassuring for the cancer. Suppress TSH!

Hypothyroidism?: Levo dose may need to be adjusted according to TSH level. See your doctor.