Hi, Jane. I'm not really sure about this, either, and I also have this to deal with. Two things: a farmacia in Europe is not much like a pharmacy in the US--they treat a lot of things we have to go to an MD for, so probably they could give you a shot. (However, the protocol is a lot different in some countries in Europe these days, and some places are going more to the high-dose oral treatment, so you might not necessarily find a farmacia with B12 in stock. Incidentally, they don't use cyanocobalamin but a different formulation, not sure what it's called.)
However, I also have pernicious anemia, and if that's what you've got, I'd urge you to learn to give yourself the shots. It will make the rest of your life a lot simpler, and a syringe and a single dose ampule of cobalamin don't add much weight at all to your pack. Just ask the nurse the next time you go. In my case, they didn't want to do that at first because they wanted to keep an eye on how I was responding to it, but once I was stabilized they were happy to teach me.
EDITED for typo