My wife has Graves disease and had the iodine pill. She has to take synthroid for the rest of her life, and she has to get blood work like 1-2x a year to make sure her levels are right, expecially when she was pregnant. It's great that your doctors found out what it was rather quickly. My wife was sick for a year since doctors kept misdiagnosing it. She used to have heart palpitations, tremors, extreme fatigue, temp flucs, and every other symptom that it can affect. She's fine now, but will be on synthroid for the rest of your life. There are some really good books out there on how to live with hypo/hyper-thyroidism....but since you're doing the radioiodine treatment, you prob will be back to normal rather quickly.
One thing is, we have to pay for the synthroid name brand since the generic still produces some side effects. But it's not too expensive. Right now she takes 88mcg daily and 3 months supply is $120. The generic is $5 for same supply.