D., I also have a low thyroid, and hypothyroidism. Yes, pretty much once you have this, you need to be medicated the rest of your life. It is critical, so that your metabolism is working properly. If you ever want to get pregnant again, it's CRITICAL to have this under control. If not, it can even keep you from conceiving, or one pregnant, if out of wack, it can cause miscarriage. I remember being very frustrated and sad about that in the beginning. Now, it's a habit, and I realize that it's not much different than those who have to take heart medicine, etc. And I also tell myself, that this is not due to old age or anything like that. Sometimes, it can come on after a pregnancy, and they don't really see it, because it can mimic post-partum depression, and tiredness, etc. This is what happened to me. One thing that really helped me was reading Mary J. Shomon's book, called "Living Well with Hypothyroidism." She is a leading expert on this subject, having the condition herself. She also has several other related books, like "The Thyroid Diet," which deals with managing your metabolism for lasting weight loss, ect. She is excellent at helping you to understand what is really happening to your body, and your options at helping it. I think you are lucky to have a doctor prescribe Armor thyroid. I'm just on the generic, Levothyroxine. There are some foods that work against the absorption of the meds, like Walnuts. High fiber foods also interfere, so they say not to eat them until you've given yourself an hour. I take my meds early in the morning, then eat an hour later. Also, take your vitamins at least 4 hours separated from your meds. I actually take mine at night before bedtime.
You need to have your blood levels tested every 6 months or so AFTER you know your thyroid is stable. For now, it might take up to a month or 6 weeks to do that...or more, depending on your own body, and how much work it has to do to reach your "norm." To be proactive, I ask for copies of all my bloodwork, so that I will KNOW what the levels are, and how they fluctuate. Some doctors will say it's normal for a level up to 5, but for trying to conceive, you need it under a 3. Mary Shomon is great for explaining all these things. I highly recommend buying her books. Here is her website, that should help also: http://thyroid.about.com/
Hope this helps.