Hi Joy!!
My name is Amanda and I am hypothyroid too. I was diagnosed when I was 9. However, don't think that I understood it that early!! I take Levoxyl and have for years. I've taken medicine so long that I know when my levels are off all on my own and I just go to the doctor and he tests me and says "yep you're right!!!"
You can battle your weight!!! You have to have a lot of determination though. Not because you can't do it...but because you have to get past the initial tiredness that you are feeling and boy do I know that feeling all too well. Until you battle that and win (if you kick it in gear with no cheating for about 1 week - you'll feel yourself win over it) then you won't be able to get your metabolism in kick-start mode.
I hate when people tell you "the only way to losee weight is..."
so let me tell you that all of this worked for me and it may not for you but we're all here for suggestions anyway right?!?
With hypothyroidism - starving yourself works against you. Hypothyroidism already causes your hormones and metabolism to work against you so you have to help it. I NEVER skip breakfast. I have 5 small meals a day (3 meals - 2 snacks). This keeps your metabolism going all the time.
Choosing extremely healthy foods for the first part of your weight loss is important too. I weighed 212 lbs after exiting the hospital with my son 4 1/2 years ago. I'm down to 155-158 just depending on what day of the week it is. I've maintained a weight loss of about 20 lbs a year and I've kept it off this way. As much as I would have liked to have lost it a lot faster - I have to admit that I hit lulls in my weight loss quite a few times and "gave up" dieting for a little while each year only to get right back on board after gaining back a few pounds.
I'd love you chat more with you - I just need some direction. I'm a chatter as you can tell from this message being so long. Let me know if you have any questions.

A supporting weight loss buddy