Welcome to NeuroTalk:

I wonder.... have you had a blood test for B12? Low B12 is very common in US. It is sneaky here because our lab ranges have not been adjusted to the newer cut off level (higher) for tests.
The new suggested lowest normal here is now 400.

Still reports do not flag as abnormal levels below that.

So if you have had testing for this, ask for the numbers and come back here. Many doctors still say "normal" or "fine" when people are very low.

One diagnostic sign is the Romberg's test. This is done with a person behind the patient, not touching. The patient closes their eyes, and if they fall back and cannot keep upright, signals a potential low B12 level. Other signs are numbness, tingling in hands and feet, fatigue, poor sleeping. Lots of vague things.
Romberg's test also may indicate other problems like ataxia, and neuropathies.

Here is my B12 thread, with medical links:
http://neurotalk.psychcentral.com/thread85103.html