I Ha Total Thyroedectomy 4 Years Ago And Had My

I ha total thyroedectomy 4 years ago and had my radiation treatment after my operation. I was advised by my doctor way back home to have my thyroid pill and last month I had my thyroid test and according to my doctor my thyroid count is too low so she advised me to stop my thyroid pill for a month and now I can observed the changes in my body without the pill. I'm just worried if the cause is without taking my thyroid pill