I have B12 deficiency

I am a  57 yrs old African-Amer. woman who for the past 17 years experienced hair loss but could not get an answer from my dermatologist.  About 3 weeks ago I was diagnosed with b12 deficiency.  I did some research and they say hair loss can be caused by "b vitamin deficiency".  I am menopausal, suffer from hot flashes.  I have experienced some muscle twitches but I thought it was due to too much execersing.  My memory is not as good and I thought it was due to estrogen depletion.
My GP started me on B12 shots monthly.  She had blood work done and said my b12 was 204 and (b12 range from 200-1200). She also did thyroid test and that is normal. I'm a little upset with my GP because she never mentioned that I could give myself these shots at home and that sublingual b12 tablets would also help with my energy. This is the only tests she has to come to the conclusion of "b12 deficiency". Is it enough or should I see someone else?