I'm glad you got a dx. Just so you know, thyroid issues can make one more susceptible to problems such as cancer (I have a bad thyroid and adrenal fatigue, and my specialist told this to me). If you are not already doing so, you may want to look into boosting her immune system and giving Harlow a cancer preventative lifestyle.
Good luck with the meds. It does take awhile to regulate the thyroid with medicine, but it can be done.