That definitely sounds like it may be the culprit. My OBGYN wants me to go on a low dose HRT, but I have not (2 kids in college and it is very expensive, plus there are risks). If I were you, I would at least start taking a B complex. My neurologist said that everyone over 50 should take it. It contains B-12 but at a lower dose. My mom and 3 other women that I know have recently asked for their B-12 levels to be checked (after what I experienced) and their numbers were all lower than mine. They were all told to take B-12. I think as we age and our hormones fluctuate, our B-12 levels are adversely affected. It is also my understanding that your body will excrete any B-12 that you do not need so you don't have to worry about taking too much. I take 1000 mg daily.