Low white blood count

I am six weeks post op and had my first blood work done. I was getting my B12 shot today and saw the results on my file. I asked the assistant what it meant for my WBC to be so low. It was 2.2 and it is suppose to be 4.0 - 11.0. She said that it was probably because I haven't had a B12 shot and not absorbing my vitamins. I don't see my doctor until next Wednesday so I'm just wondering if anyone has every had their white blood count so low. Also, my middle back is constantly in pain. I don't know if that's a positure problem or if it's related to surgery.

I am almost tey years out and have had back pain and kidney and bladder problems. I just got blood work back and my white blood count is low. I am wondering if this is because of the surgury?