Blood test results

Please I wonder if any body can answer this for me, I have had m s symptoms since July last year, have had MRI scan which showed up leision, have seen the Nero Who told me it was properly m s but without going further text can Not diagnose this on paper, so I am waiting for lumper pucture and further tests. I went to the doctors last week as I was feeling really poorly and insisted that they done some blood tests on me, my question is my blood test results came back today and showed I have a b12 deficiency but doctor can not see me till Friday, so question is is it Possible the b12 deficiency that could be causing all my symptoms or could it be m s causing the deficiency in the b12 and is it common to have low b12 with m s , hope this makes sense Many thanks