I had my thyroid removed due to cancer 8 yrs ago. My dr prescribed 175 mg levothyroxine which i took for the past 7 years. Approximately 1 yr ago my doctor determined my t4 was too high and ask me to alternate 150 and 175 mg. about 6 months ago i switched doctors and upon having a new blood draw, she told me my tsh was way too low and put me on 137mg. A month later I retested and it was still too high, so then I was given 125. A month later, still too high, now I am on 100. What could have changed that would cause this? My last test showed T4 at 1.4 and TSH at .14.