It takes 4-6 weeks for the Synthroid to reach full potential in your blood, so it's unlikely to have anything to do with the active ingredient, which is levothyroxine.
It's possible that your doctor started you on too high a dose, but, again, it wouldn't be in your system this soon, I doubt you'd be feeling that, yet, either.
The 50 mcg tablet is white, so it doesn't have any dye in it, so that pretty much leaves fillers/binders.
The first thing I'd do is try splitting the pill in half for a while, in case it is, simply too high a dose. The next thing I'd try is a different brand of medication and starting 25 mcg, rather than 50. Most people do well with Levoxyl.
Armour is desiccated pig thyroid and pigs produce much more T3 than humans do. You don't have a Free T3 test, so you don't know if you need all the T3 that you'd be getting with Armour and I wouldn't necessarily recommend that route, at this point, especially, if your doctor isn't well versed in thyroid care.
I forgot to mention that it's not unusual for symptoms to get worse or for new ones to appear when one first starts taking thyroid medication, but they go away once the body becomes accustomed to the med and to having the hormones we've been doing without. Often we just have to keep taking it until we get used to it, like we do with many medications.
I had a TSH of 6mU/L and free T4 of 13 and was started on 50 mcg daily and I was hyperthyroid for a week and then worse hypothyroid symptoms for a month since my natural thyroid hormone production slowed down in response to medication but finally the medication built up and did a better job then my thyroid gland. If I could start over I'd start at a lower dosage first and increase if needed after 6 weeks.
Thanks both. I just posted a new thread with an updated test result. I'm thinking that I will stop for a few months and start more slowly if I try again (although I thought 50mcg would be pretty slow for a 180lb guy....)