I have been getting b12 injections every 8 weeks for about 3 years after a struggle with the GP. I have now changed jobs and moved areas the new GP won't inject me every 8 weeks stating that 12 is sufficient. I had a blood test straight after the last injection. I am now week 10, I have an appointment with him tomorrow and feeling totally exhausted headaches dizzy etc. how can I make him see that I could survive only 8 weeks but any longer I just can't function sleeping 9/10 hours a day more if i could?