You should also DEMAND to be tested for more than just TSH.
you should also be tested for both Free T4, and Free T3.
This tests for the hormones that are "free" from being attached to a protein. Once the thyroid hormone gets attached to a protein it becomes USELESS. So the ONLY hormones that are used are the "free" hormones.
T4 is a "storage hormone". That is, the hormone is not directly used. It remains in the bloof and available. Whent the body senses the need for more thyroid, it will convert the free T4 hormones into T3 hormone molecules. And again only the "free" unattached T3 hormones are ultilmately used by the cells in your body.
As you can see now why it is so important to test for the FREE hormones. (not "Total" which counts both the free and attached hormones. And without knowing how many are free and thus available, the "total" test is outdated and of little value).
If you have your blood lab results, please post them here along with the reference ranges. As different labs use different reference ranges.
It's very possible that your doctor started you on too high a dose of Synthroid, but it should be noted that chest pains and palpitations can also be present with hypothyroidism. Additionally, it's not unusual for symptoms to worsen or for new ones to appear when starting a new thyroid med, changing meds or dosage.
There are other meds you can try. One is generic levothyroxine, another is Levoxyl. They all have the same active ingredient - levothyroxine sodium. The difference is the fillers/binders.
It's customary to start thyroid hormones at a lower dose, and work up, as tolerated, in order to avoid adverse reaction. It takes 4-6 weeks for Synthroid (as well as other replacement hormones) to reach full potential in your blood, so if you had that reaction sooner than that, you might have been reacting to the fillers/binders, or possibly anxiety.
There's a good chance that all you need to do is start the Synthroid at a lower dose; possibly 25 mcg, then retest in 6 weeks and increasing as needed. Going up by smaller increments helps avoid reactions.
Are you still taking the 75 mcg Synthroid? If not, what are you taking?
The whole thing can be scary, but rest assured that the chances of your dying before the 9th, due to thyroid is basically non-existent.
As far as supplements, you should talk to the doctor treating your Hep-C, because some that we take for thyroid, might be contraindicated with Hep-C. I, personally, take selenium, calcium, magnesium, vitamin D.