If your vitamin B12 deficiency is mild, you may not have symptoms or you may not notice them. Some people may think they are just the result of growing older. As the anemia gets worse, you may:
Feel weak, tired, and lightheaded.
Have pale skin.
Have a sore, red tongue or bleeding gums.
Feel sick to your stomach and lose weight.
Have diarrhea or constipation.
If the level of vitamin B12 stays low for a long time, it can damage your nerve cells. If this happens, you may have:
Numbness or tingling in your fingers and toes.
A poor sense of balance.
Dementia, a loss of mental abilities
Hello~Yes, having a B12 deficiency can cause a lot of the symptoms you mentioned. I have had B12 shots, and the results were amazing, I felt full of energy, and my depression lifted as well. B12 is a very important vitamin, but, I would like to add that it should be taken in conjunction wit Folic acid and the other B vitamins, they all work synergistically, and it is best to have the entire "team" working together.
As to the ectopic beats (missed beats) well, sometimes it helps that too, sometimes not, each person is different when it comes to those. I have them and I hate them, the shots did not help that part, but the rest it did. The reason it did not help the "flutters" is because it was causing more energy than before and my heart was over reacting to it. You may not have that problem at all, everyone is different, but it might happen.
As to what questions to ask your doctor, I would just ask what you have asked here, they are good questions and he/she will be able to answer than I have I am sure.