I've been looking into the psych symptoms of hypothyroidism and apparently they are vast. My gf of nearly 8 years who told me 1 month ago unprompted "you're it for me, I hope you know that. No matter what happens" and smiled just told be several days ago she may not be in love with me anymore but hasn't cried in weeks even during sad movies/videos or during recent arguments which are very serious in nature due to her psych symptoms and undiagnosed thyroid issues(mother had total thyroidectomy and graves, aunt had hashimotos and diagnosed schiz with no symptoms after thyroid treatment really). She seems sociopathic at least if not completely unable to empathize, makes crude jokes during sad moments etc... she is not herself at all. It's absolutely devastating to me, but at least she's not suffering through these symptoms. If I can take these hits for her I will gladly as long as it doesn't cause irreversible damage. It seems likely that thyroid could be the cause based on my experience alone anyway.
The thyroid controls many body process, including, but not limited to metabolism, heart rate, body temperature, etc.
Please see my comments in the following thread, so we can understand your situation and answer your questions more fully:
http://www.medhelp.org/posts/Thyroid-Disorders/Life-Expectancy/show/2983647