C.C.
I would double-check your TSH blood tests (for thyroid... assuming they tested you for that?). Your TSH should be between 1.2-2.0. Anything higher than that, and your thyroid is not functioning properly. A lot of doctors are working off of an old TSH scale that says that 0.5 - 5.0 is "normal," but it's not - so be sure to ask specifically what your TSH test number was. I went through this myself less than a year ago where my hair was falling out in clumps, among other problems (my period was never-ending and super heavy, my skin was a mess, I was gaining weight for no good reason, lethargic, depressed). My TSH was 4.9, so my doctor was trying to argue that my thyroid was normal. Anyway, switched doctors and finally got someone who knew what she was talking about. She put me on thyroid meds and I felt so much better within a few weeks. My hair stopped falling out and did grow back in.
Anyway, your thyroid can cease to function properly at any time and one of the major symptoms is hair loss, so I would check into that. Good luck, I hope you can find out what's causing this problem!