I suffer from low b12 levels - 130 which were corrected 3 years back with b12 shots ( neurobion injections 1000 mcg) . However, since my body is unable to absorb b12 from food, I had been taking b12 shots every 3 months till last year.
However, for the past 6 months I am unable to take b12 injections as it results in an extremely high anxiety state - 2/3 days after taking the shot.
I had tried tablets, but it results in the same reaction. I am even unable to take b complex vitamins with just 15 mcg of b12.
Aside: I also suffer from anxiety and take 0.5 mg x 2 clonozapem tablets for the same.