Hi PenguinMom I was having the same symptoms as you (fatigue, dizzy when standing, mood swings) and had a blood test done. RBC was very low, my doctor thought it was B12 and gave me shots to administer every three days.
The have been feeling better but the results are complicated due to other factors.
Your symptoms sound like B12 anemia, low vitamin D can cause tiredness and depression (it is the major factor behind SAD, Seasonal Affectedness Disorder), but not likely dizzyness.
An injection of B12 enters the bloodstream almost immediatly so your 2nd test results would seem to be due to the shot.
I do have a question though, where do I get B12 shots? I've moved and as my last doctor (natropath) just gave me the shots I thought it would be easy to get another docotor to do the same (I have my blood-test results) Apparently not, I can go in and have a doctor administer B12, but I don't want to go to a doctor every 3 days! Any advice would be greatly appreciated.
Do I really need to take shots every 3 days? BTW I have tried sublinguel B12 (for 6 months) and my when tested RBC was lower.
I've been having a hard time finding a doctor who can answer simple questions, so have been trying to figure this out myself, but still don't understand anything.