Your symptoms could be caused by any number of problems. Thyroid comes to mind first, but only because that's my problem. Thyroid issues can cause the vast majority of your symptoms. It can even cause your twitching, heavy menses, and anemia.
My second thought is that it could be Celiac, which is a sensitivity to gluten, and that can cause muscle spasms, fatigue, pain, dizziness, hot feet at night, and a whole host of other issues.
Don't let the dr write this off as anxiety. Either he listens to you or you find another dr.
Good luck and keep us posted!