If you are having a loading dose of injections and will move onto a maintenance dose when your levels have risen I wouldn't mess about with sprays or oral supplements. That will falsify the results when your levels are measured.
I have had quarterly injections for years now. I can tell when they are due, as I get very tired, I forget words more than usual, and other symptoms kick in, After the injection, I don't immediately feel full of beans. The drug must take effect slowly, so it's not a case of feeling great after the injection, but of feeling low when it wears off.