One: get a copy of your "normal" lab report, and check the actual number for your B12 level. Neurological symptoms can present with levels as high as 400, yet lab lows are typically set around 150. You want to be sure you are in the upper quarter of range or over the top. I had many many B12 deficiency symptoms with a NORMAL level of 294.
http://jccglutenfree.googlepages.com...ciencysymptoms

Also, other nutritional deficiency can cause PN, including vitamin B1, B6 and E. And gluten sensitivity, defined by the presence of antigliadin antibodies, can cause neurological disease even in the absence of biopsy proven celiac disease. This is a point of contention in current medicine, but the research on it is ongoing and seems to be proving its case.

Here are pages from the gluten file that are especially pertinent for you.

http://jccglutenfree.googlepages.com...ationsofgluten

http://jccglutenfree.googlepages.com...eralneuropathy

http://jccglutenfree.googlepages.com/diagnostictesting

http://jccglutenfree.googlepages.com...niggantibodies

http://jccglutenfree.googlepages.com...sceliacdisease