12 years is a long time to continue with hypothyroid.
First, have you read Dr. Brownstein's book about heaing thyroid? Do you take any medications for it and what are they?
Do you know Iodine is a necessary element and can help hypothyroid?
Flaxseed is good in a raw form. Sugar in no form is good for you. So I would quit Sugar totally and look for green Stevia powder. It is 300% sweeter than Sugar and does not have the negative effect of sugar.
Go to Iodine forum here if you have not already done so.
Lastly, blood tests are not so accurate to know if you have thyroid problem or not.