Hello sanguine_speed,
I have been reading this whole thread, having just found it today. I know what it is like to feel like you are offering so much, getting so frustrated and then to begin to resent your baby and I am so glad for you that things have gotten way better and you have come out the other side. Congratulations!
I am writing about the thyroid issue you are investigating. I developed hypothyroidism (underactive) after my first baby at about 5-6 months post-partum. I likely had hyper that changed to hypo, as this is very common. I would venture to say that most docs, even endro specialists, are not aware of the sensitivity of the blood tests for thyroid disease. What I mean is that there can be many occasions when the tests come back normal, when in fact a thyroid problem exists. Docs (and others) who know this, use a much smaller range for "normal" than the range provided by the labs and used by most doctors. For example, for TSH, labs will say that .5 to 4.5 is normal. However, most women feel good between 1-2. Personally, I need to be close to 1 and I can tell from how I feel as to when I am under .5 or over 1.5. The problem of course is that we, the patient, can learn that we have normal labs when we still feel off. Often we are told (in one form or another) that we don't really have a problem or we are MIS-led down another road - for example, to anti-depressants, or such. I hope you are able to learn the actual test results of your labs so that you can do a little research yourself.
I am happy to provide more information - websites, books, personal experience if you would like. I was so angry not to be properly diagnosed because I felt like I missed out on my time with my baby (and my life) while my thyroid was whacked out and I was not treated in a timely manner. For this reason, I urge anyone who thinks they MIGHT have a problem to check it out - you can save yourself (and your loved ones!) a lot of grief. Here is a place to start (see links to checklists of symptoms too):
http://thyroid.about.com/library/links/blthyroid.htm
Good luck!
Robin