I have had hypothyroidism for many years. This last year I have been struggling with fatigue, heart papilations and a constant underlying headache. My TSH in July 2016 was 0.03 my T3 4.5 and my T4 18. My synthroid was reduced to 125mcg (I was taking 150mcg) and I was put also on Cytomel 25mcg ,which I took twice a week. I have just got another TSH level done and the results are > 0.03. What is the cause of this, has my hypo turned to hyperthyroidism and are these doses doing more damage than good?