I was damaged very badly by then, yes combined degeneration.
I don't have the digestive symptoms, but many people do not. Ironic to be dying because of a severe digestive problem and have no digestive symptoms, but that is what was happening to me. Also I was gaining weight rapidly: so many ignorant doctors assume that all being damaged due to malnutrition will lose weight, but of course that is not true at all.
I hope you will go to my website under construction (link below). That will answer some of your questions about B12.
Also I hope you will do some reading on Cara's site, which will address some of your food sensitivity issues:
http://jccglutenfree.googlepages.com/
rose