Hi Doctor, I am an NRI, from last 10 days I am suffering with mild fever, body pain, heavy weakness and head spinning. Recently I have done blood check up and found low vitamin b12 levels (having injections). Recently I had head collision with wall but not major (ended up with 2 stitches). Not understanding what happening? is it any viral fever is there or any other problem is there? could you please suggest me ASAP. thanks, Ramana