Sorry for the issues you are having, but welcome to the forum.

That B12 number does sound somewhat low, so it wouldn't hurt to supplement with some methylcobalamin.

As for the other symptoms, it certainly could be some form of PN, but could also have other causes (including MS, as you have mentioned.)

I would think that they would want to have MRI done on the brain and cervical spine - to look for any issues there.

After that, things get a little murkier - there's a whole boatload of other tests, but you may need to get hooked up with a good neuro to start moving down that road.

best of luck