To be honest, most doctors really don’t know enough to help with conditions like ours (unless you find a functional/holistic doctor). I’m in Australia so can’t help you with leads for Rhode Island, but if you jump into any of the online PA groups I shared in the article, there are people who live in your area who may have some leads.
Be sure to get your Vit D checked as it seems there is often a link between B12 deficiency/PA and D.
Please don’t wait till you get into a dark place to have your shot, try to inject before symptoms return. Have you investigated self-injecting? You can buy all the materials you need online either via Canada or Germany and many people are doing that now.