My doctor prescribed Armour Thyroid to me to help me lose weight;...

I suggest you make an appointment with an endocrinologist ASAP. It could be the doctor is unknowledgeable of proper treatment of a thyroid disorder, which you say was never there. It sounds more like you have a thyroid issue after stoppping.

The problems you are having with Armour are due to low cortisol (adrenals). Many people that switch from a T4 only medication to a T3/T4 find problems with heart palps and being anxious because the additional T3 brings out the low adrenal issue. Few doctors even admit that there is a thing called adrenal fatigue, however you will find holistic doctors familiar with it. Until you address the adrenal problem you will likely have problems with at T3/T4 medication. On the other hand, if you have problems converting T4 to T3 (an a LOT of people do), then T4 medications like Synthroid and Levoxyl will leave you feeling achy and fatigued and with hair falling out. Most people find that they need to be on 3-5 grains of Armour (180mg - 300mg) to relieve all hypo symptoms. It takes a special doctor to know this. Armour will suppress your TSH and it is a lousy measure of Thryoid function. A better test (if you can convince your doctor) is a Free T3 and Free T4 test. You need your FT3 to be at the top of the range and your FT4 to be mid range to feel good. Take a look at this site: http://www.stopthethyroidmadness.com/

Thyroid replacement medicines should never be given for weight loss unless the person has a thyroid problem that is causing the weight gain. This is just another example of why I take all of my medical care into my own hands, doing extensive research, then getting second and sometimes third opinions on my conditions and always asking a good pharmacist some questions as well. Pharmacists sometimes know far more about the actual medicines than doctors...doctors study more about what to give you, pharmacists study the medicines themselves.