Would move forward w/ I-131 ASAP given TSH level so you can get on levothyroxine replacement...
Next time you need a scan or More I-131 treatment insist on using thyrogen instead of coming off medication for a month. I am now seeing a new endocrinologist and he told me how dangerous, old school practice and unnecessary it was for me to be off thyroid meds for a month, I used thyrogen for a scan this year and didn't suffer at all. It's expensive but with the history of cancer the insurance company will cover it.
Thanks. Had my I131 and now home. Will start my synthroid again in two days.