Yes, it is possible that your low B12...is giving you symptoms.

Dr Snow is on that link Jo gave you, his paper from 1999 explains how some people have neurological symptoms in the low ranges of B12 testing.

The new low is 400pg/ml. The lab ranges have not changed at all since a decade has passed that 400pg/ml has been suggested to doctors. And they still cling to their old therapeutic manuals and are resistant to change.

http://www.aafp.org/afp/2003/0301/p979.html

Also people with the DNA mutation..MTHFR cannot methylate B12 properly to activate it to actually work in the body. A test of MMA will show this ... a low value result is good showing B12 is metabolizing MMA properly. A high value shows poor methylation and poor B12 actions.

Many people have this mutation, so it is worth getting. That is why the recommendation to use oral methylcobalamin now instead of cyano (which is not active). If you have this, and/or pernicious anemia, you need to start oral methyl B12 now.
If you are vegetarian and not eating animal sourced foods... also this leads to low B12 levels. Oral is adequate treatment, if you take enough, as B12 is not absorbed well. 5mg methylB12
on an EMPTY stomach once a day will raise you to about 1000.
After you replenish with 5mg you can drop to 1mg a day, but many of us here keep the 5mg. MethylB12 is not expensive and easy to do. You may have to keep taking it for life.

You can come to our PN forum and start reading that B12 thread, and ask your questions there.