I am also dealing with hypothyroidism. I was diagnosed in May and the past few months have been up and down due to trying to get me on the right level to regulate it. The last two or so months were NOT good as I was not on enough of a dose and I was dead tired all of the time. Not much fun and not helpful if you need energy to exercise! I think I am at a good level now as my energy has returned and other symptoms have subsided a bit.
Check out the dieting with obstacles section of the forum. There are people there who are dealing with this condition and give great support. Of course join us here as well!
Good luck.