Hypothyroidism Support Group
Hypothyroidism is the disease state caused by insufficient production of thyrohormone by the thyroid gland. There are several distinct causes for chronic hypothyroidism, the most common being Hashimoto's thyroiditis and hypothyroidism following radioiodine therapy for hyperthyroidism. Advanced hypothyroidism may cause severe complications, the most serious one of which is...

http://thyroid.about.com/
Taking the medication is going to be a bit of a process. Usually you start out at a low dose, take that for 4-6 weeks, and then retest all of your thyroid levels. If that dose isn't enough then your doctor revises your prescription up and you take that for 4-6 weeks and then retest. Rinse and repeat. :) Eventually you'll hit the sweet spot where you're at just the right dose and things will feel better, but it is going to be a bit of a process to get there.
You also need to make sure you keep copies of all of your thyroid lab work. And testing TSH isn't enough - your doctor also needs to be testing Free T3 and Free T4.
I'm looking forward to getting to know you and I hope you feel better soon!
so -- we'll see, should be an interesting journey ;)