Thanks everyone for the replies!
I had the radio iodine therapy few years ago and I'm taking thyroxine ever since.
I don't know what the "cause" of hyperthyroidism was, but it probably wasn't Graves - I had no usual symptoms (eyes, etc). My only external symptom was my neck, which was A BIT bigger and was only noticed by my doc when he was checking my throat when I had a cold. Otherwise no one would notice.
I was 13 when diagnosed, but I remember that before that I simply had tons of energy and could eat any amounts of food without changing my weight
My BP was always "perfect", I was hardly getting cold in winter and sometimes my hands would sweat... But to be honest I liked my hyperthyroidism! I had lots of energy and could eat anything
After the iodine therapy I gained a lot of weight (no one really explained to the 13-year old what was going to change), which caused a lot of problems with my self-esteem. Even though my BMI was in the "normal" range, just at the top end
I noticed that as long as I have my thyroxine dose right and my docs are not messing with it (which was also a problem recently) and I let my TSH normalize, my weight comes off by itself and my body kind of "balances" itself out
For the iodine therapy, I remember I was given a pill and had to stay at home for some time and that was it.