hyperthyroidism

Hi im kind of "new" here I havent used the app for over a year or so and I wanted to ask you guys a question, so last May I ended up in the ER because I was having really bad heart palpitations and over 140 heart beats per minute long story short I was told i had hyperthyroidism and that was causing my symptoms got sent home with meds etc... I have been reading a lot and found that sometimes after u have a baby u get this thing called thyroiditis but the doctor keeps insisting its graves disease and wants me to get an uptake scan but im so scared because that for the scan i need to take radioactive iodine and the word radioactive scares the crap out of me. has anyone here beem diagnosed with hyperthyroidism or graves disease after having a baby. I forgot to mention I had a baby in june 2016 and started having symptoms nov. 2016