The body maintains electrolytes, fluids, pH, etc. in a very tight spectrum. Anything outside of that can reflect things such as metabolic acidosis/alkalosis and respiratory acidosis/alkalosis.

A neurologist is not a pulmonologist. A pulmonologist is not an endocrinologist.

I highly suggest that you see a pulmonologist to assess if you have something like respiratory alkalosis.

One of many articles on the imbalance of CO2.

http://emedicine.medscape.com/article/301680-overview

They could do an arterial blood gas to check all signs of how your breathing is.

Yes, the B12 reading is fine. The CO2 needs further evaluation, in my opinion, especially if you are having any breathing issues. But sometimes you can't tell if you are!

Annie