A TSH that high means your thyroid is producing no hormone which is the object of RAI. In other words, your thyroid has given up the ghost and you need replacement hormone, levothyroxine. I had a TSH of 40 on methimazole early on and I felt the worst of any time during the entire course of the disease. If you do not hear first thing Monday, keep calling until you do. You must be feeling bad with a TSH that high.