Hi K.. I take Levothyroxine since my thyroid is underactive. I don't have any trouble taking it, but I've never taken Synthroid so I don't really have anything to compare it to. My mom has been taking thyroid hormone since she was 16 though, so she's got considerably more experience. She took the Armour stuff for the first 20 years she was on it. Armour is thyroid hormone extracted from pigs (gross, I know), and from what I understand, it's not like Synthroid or Levothyroxine (S&L) in that there's no dosage....you just take it and your body uses only what you need, but it contains a "normal" balance of T4, T3, T2 & T1. Also, many doctors won't prescribe Armour since there's less control of the dosage. S&L are made in a lab, contain only T4, and the dosage is tightly controlled (i.e., pills come in 50 mcg, 88 mcg, 100 mcg...). Your body naturally degrades the T4 into T3, the T3 into T2, and the T2 into T1, so generally there's no need to take T3 unless your body can't break down the T4 for whatever reason. My mom has told me numerous times that there are bad batches of both S&L (she's taken both), and I've seen what one of these bad batches does to her: it's like someone put her on slow motion. If you think you might have a bad batch, you can ask the pharmacist who filled your prescription (they may have gotten information from their manufacturer), or talk to your doctor.
Depression and weight gain are both common symptoms of insufficient thyroid hormone. Unfortunately, you may have to deal with these symptoms for several weeks until your hormone levels return to what's normal for you. Since it takes awhile for your body to return to normal, it's possible that your dosage may still be a little low (maybe you should be on 112 mcg), but your doctor won't up your dosage for at least 4-6 weeks since your last dosage increase. Remember too that your "normal" is not necessarily the same as mine or anyone else's (always ask for your TSH test results!). But, you know when something's not right with your own body. You can always call your doctor's office....even talking to a nurse about your symptoms may yield valuable insight. Also, you might want to consider keeping a log of when they change your dosage, and any symptoms or cessation of symptoms you experienced. I know how hard it is to go through this - trying to get a thyroid condition sorted out - and the havoc it causes in your life.