The classic symptoms of B12 deficiency are persistent fatigue, tingling or numbness in the hands and feet, problems with memory and concentration, mouth ulcers, a sore red tongue, and pale or yellow-tinged skin
I would recommend this location
Adults over the age of 60 are much more likely to experience this issue, but it can happen to people of all ages
A majority of reported events occurred in patients who had experienced gastrointestinal reactions such as nausea, vomiting, diarrhea, or dehydration
The headaches seem to follow a different pattern (from what I remember) and tend to lessen over time - I had problems with headaches when I started using methyl but (nasal rather than injection) but it went away after a week or so
Treating the deficiency can often reverse these symptoms