Hi, I was recently told my B12, folate and iron were all low (124, 3 and 12) so I've now had the six B12 loading doses plus taking folate and iron tablets. Don't feel much improvement so far - still tired, having palpitations and heart rate goes too high when excersising (e.g. over 230 BPM if doing speed work or hill reps when running) so I've had to slow down and avoid those sessions. However, I have started getting pins and needles in my hand which I didn't have before. Reading through other posts I'm not sure if this is a normal response to my body trying to repair itself or it's something I should go back to the doctor about? Anybody help please?