C.Y.
Congratulations on twins! Re the hyperthyroid, if you're into natural solutions, you might look into coconut oil. I know, it sounds a little crazy, but it's supposed to improve and normalize thyroid function, and as a bonus it contains a great fatty acid profile that's especially beneficial to breastfeeding babies. For more information see the book Eat Fat, Lose Fat by Enig and Fallon. It sounds like another diet book, but it includes a health recovery program and info about coconut oil. Also interesting is The Coconut Oil Miracle by Bruce Fife.
Good luck!
C.