Is this a vaguely healthy diet with my underactive thyroid?

It's a little heavy on the carbs. I would suggest switching out a hard boiled egg, turkey, or a cheese stick with some of the fruit and eating more green vegetables (lower in calories and carbs but still have lots of nutrients like fruit). If your thyroid is still low on the medication, you either need a higher dose or you need a different kind of medication. Doctors usually prescribe T4, but a lot of bodies cannot convert T4 to T3. My doctor prescribed me T3 AND T4 (I take Naturthroid) and I feel a lot better on that than I did on just T4 (which was Levothyroxine). Ask your doctor about either taking Cytomel (supplemental T3 along with the T4) or switching to Naturethroid or some other kind of T3, T4 medication. Also, ask for a free T3 blood test, that will show you far more than a T4, TSH blood test. Look at the sites in sources, they will explain more. :)