hi there, sorry to hear you're dealing with this symptom.
i don't believe b12 is the only b vitamin they should be checking in your case - b1 and b2 could stand to be looked at also.
what was the b12 level, iima? there's 'fine' for hematology, which is how we currently define deficiency (wrong!) and then there's fine for everything else, which is a higher level.
you might want to get a really high quality high potency b vitamin supplement, like a b50 complex.
the best thing i've seen in b-complex supplements lately is the use of the methylcobalamin form of b12, rather than the cheaper and less bioavailable cyanocobalamin form. watch for that. the brand 'new roots' has a product like this.
you would also do well to investigate whether you consume enough b-vitamin-rich foods on a regular basis.