I just got my B12 shot(10000 cc) on the 7th of this month,I have been getting them for as long as I was diagnosed, which is 6 yrs.The Dr. did'nt tell me how to titrate down I just got fed up with the headaches and not sleeping for more than 3-4 hrs a night and stopped taking them.I figured The dosage was pretty low and that it would'nt really hurt me to quit.I just feel so fuzzy headed,maybe I just need a really good nights sleep.I don't know how long it will take to get the med out of my system,I've been on it since the middle of May. Thanks for the help and info.abby2