hi m, welcome to TIMS
sounds like they're early on in the investigations, but doing the right stuff to start figuring out what's wrong.
FYI, if you have one deficiency you can have related ones with other symptoms - tremor can in fact be a b12 deficiency symptom, though.
i'd advise you to be skeptical if they tell you your results are 'normal'.
when you have symptoms, 'normal' isn't good enough.
there are a lot of sick ppl out there with levels in the 'normal' range, but those levels are still significantly different from healthy controls.
for example, b12 'deficiency' is defined as values so low that your blood cells start to change shape.
you can experience cognitive issues with suboptimal b12 long before you get down to 'deficiency' though - if you have cognitive symptoms, such as memory loss, b12 could still be too low, even though not officially deficient.
if you'd like them to check a few other things that are off in MS, just in case some similar issues are involved with your symptoms, you could ask for a uric acid test and zinc test.
there's more, but that's good for starters