Thanks for the update....

You got low in B12 for a reason... which may never be found.
But whatever it is, you will need the supplement for life.
People tend to stop taking supplements when they feel better. I've done this myself, my son does it all the time.

As for the sed rate, mine has always been elevated. Not sky high, but substantially out of range. Some arthritis, sinus, ears, who knows? It doesn't take much to elevate it.

On the bright side, at least the methylcobalamin works, and you can buy it for pennies a day, and that alone is a gift!

Don't hesitate to post here, we all learn from each other.