Got my blood results back today from the 3 months after the 6 loading doses,
B12 has gone up to 689 from 117 but my iron is low so been given iron tablets,
I still don't feel any different or better then I did before the loading doses but the doctor doesn't seem to care just told me to go buy vitamin b over the counter with my own money as they won't put it on prescription but I used to get vitamin b on repeat prescription a few years back,
serum B12 when you are on injections doesn't really mean much - its symptoms that count.
Your ferritin is low but your MCH is still above range and your MCV is at the top of the range - implying that you actually still have macrocytosis (larger rounder red blood cells than normal) - which isn't consistent with an iron deficient anaemia ... and I would have expected this to have started to clear 3 months after loading shots if your B12 and folate levels were really okay.
However, I'm just a lay person and a long way from being a medical expert but it might still be worth talking to your GP and querying if the results you have are totally consistent with an iron based anaemia.
My doctor just saw that my iron was low and gave me iron tablets to take to build it up, my MCV 3 months ago was 94 now 96, and my MCH was 30.9 last time now 32.1 my platelet has dropped from 331 to 273 folate has gone from 4.8 to 10.2 ferritin from 19 to 10 b12 from 117 to 689 , I asked my doctor about not feeling well still and when I said it was 3 months since the loading doses she said that would of been out of my system ages ago so having a 689 b12 level now was good
oh dear - not a GP with much idea just how much people vary when it comes to B12.
Have you been tested for PA and other possible B12 absorption problems - may be time to start pushing for that and also may be a referral to a haematologist given that you still show signs of macrocytosis even though your ferritin is quite low.
No guarantee that referral will get you to a haemo who is any more aware of B12 than your GP but ...
This doctor was obv new as I've never heard of her till recently & I know all the doctors at my surgery , I'm gonna get them to give me another blood test end of next month hopefully it will give a better look into wants going on in my blood, might also try get appointment with the nurse who dealt with me when I had my blood test 3 months ago & arranged the loading doses & she what she says,
No I haven't been tested for pa or absorption problems
my daughters blood tests came back...( ! )
my anaemia blood results 
Help with my Daughters blood test results
My blood test results
Finally got bloods done
