The only way to truly know if you are high or low is to test the homocysteine.
Often high vitamin b in blood means a deficit.

You also need your parathyroid tested. And if your gut doesn’t have hydrochloric acid, the enzyme pepsin, and a protein called intrinsic factor you can’t absorb vitamin b. You can have the intrinsic factor tested and it should tested.

Also you need tested for blood diseases.