Dear lybrate-user, b12 deficinecy is actually more common in vegetarians. It is possible you may have less acid production in the stomach due to some cause-some medicines and excessive use of antacids can also cause this. An intrinsic factor deficiency can also be a cause. You can get an intrinsic factor antibody test to rule this out.
In any case, supplements or injections of vitamon b12 can help you get your levles back to normal, though it could take a few weeks to show any result
take care.