@Allan:

I don't know of any 100 milligram oral dose of B12.

All are in micrograms. Since you had that elevated homocysteine, you should get a B12 test. Depending on the result, you would need 1000mcg (1mg) or 5000mcg (5mg) methylB12 orally daily on an empty stomach. I would use the methylB12 because it is already activated unlike the cyanocobalamin form. Some people cannot activate it in cyano form and it doesn't work therefore.

The highest dose or oral I have seen is 60mg given under experimental circumstances in Japan to patients with MS.
But that high a dose is not used for regular people at all.

So please do get tested. And and I would switch to the methylfolate while you are at it, because people who cannot convert cyanocobalamin cannot methylate folic acid either.
Folic acid is not the active form.

You may have the DNA polymorphism genetic error called MTHFR reductase failure...this can be tested for also with a DNA test. People who have this often have very high homocysteine.