I went to my GP with breathlessness about 4 weeks ago and they diagnosed it as asthma but I asked for a blood test because I felt like I was anaemic. My ferritin was 19 and my B12 was 144. I didn't know anything about B12 deficiency but after getting my test results and reading about it I now realise that so many symptoms I've put down to age (42), tiredness and overdoing it could have been due to my B12. I felt really positive and expected to feel better after the 5 loading doses. I did start to gradually feel better while having them and even managed a run after the last injection but now a week on I feel awful and the breathlessness has returned. I am still exhausted and struggling to concentrate and remember things but even though I quoted the NICE guidelines for continuing the injections until symptoms stop improving my Doctor refused. I am not sure what to do next, do I keep going back to the GP, go private or self inject?