Hi Leandra's Mommy,
I had hypothyroidism about a year or so after my daughter's birth. I have nor have any of my family had thyroid problems, so I did not even consider it, except that I was SO tired, feeling down, unable to concentrate, pretty much all the symptoms one has with hypothyroidism.
Of course, we are all tired with a little one, but I knew something was wrong b/c I the tiredness was overwhelming and I felt not due to taking care of my daughter. Plus, I just did not feel right.
In any case, I ended up having a blood test and now take a very small dose of medication, which has worked well.
Also, don't be too h*** o* yourself about losing the weight. I breastfed for a year, too and found that it took about a year to lose weight, and still have some to shed. Everyone's body reacts differently, but again, you'll know if it is due to your thyroid with a test, I guess.
I hope you figure it out and feel better soon!
Take care!