My Dr. tested several of his patients and many of the ones he tested had a low or relatively low blood level of B12. I recall that at first he was giving his patients injections of the cyano B-12 and some had bad reactions to it. Perhaps the cyano form is not well suited for certain folks. He then switched to recommending the oral B12 (Methyl type). Some folks take as much as 5000 mcg. Many of his patients are feeling much better and my guess is that they don't miss the shots at all.

Also, please note this quote from the information provided by Mrs. D:
"Because most clinicians are generally unaware that oral vitamin B12 therapy is effective,17 the traditional treatment for B12 deficiency has been intramuscular injections. However, since as early as 1968, oral vitamin B12 has been shown to have an efficacy equal to that of injections in the treatment of pernicious anemia and other B12 deficiency states.9,17-19 Although the majority of dietary vitamin B12 is absorbed in the terminal ileum through a complex with intrinsic factor, evidence for the previously mentioned alternate transport system is mounting."

Esp. since you mention having a bad reaction to the injection, you might to inquire from your Dr. if you can try taking the Oral B12 (Methyl type), perhaps at a large dosage, and then repeat your test (s) relatively soon.