I have been posting in the past about my issues with trying to get my levels under control. I have been low and then high and now I am not sure my doctor knows diddly about thyroid issues. One problem I had was with my HR. HR would not rev up past 123 for over a year and only recently have I been able to get it to rev a little more. Not any where near in the 160's yet but it's improving. My advice is to not mess around with a GP and go to a specialist. Good luck.