One thing that surprised me, was that after having a lot of B12 replacement, the skin under my fingernails became a sort or pink... no longer blue.

And I also stopped having the feeling when I stood up that I would faint.

All my life, I mean ALL, the doctors told me that I was iron deficient, and they would prescribe iron supplements. (iron deficiency anemia)

But since I've had so much B12, that problem seems to have gone away... so now I wonder if it ever was iron, per se. I wonder if all my life I've had low B12, but was only severely affected after a few decades of pretty intense stress...

I mean, they do say that our bodies come with a good store of B12.