Hello, Welcome to HCM and thanks for asking your question. I can understand your anxiety and concern about your illness. I would like to tell you that all your symptoms are suggesting towards vitamin B12 deficiency, because body pain, mild fever and weakness commonly occur. Spinning of head is difficult to justify with B12 deficiency, but it may be because of your minor head collision and it will be ok within few days. Chances of viral fever are very less, because this mostly comes with some sort of respiratory involvement in the form of cough, cold, etc... So you can safely take vitamin B12 injections for few days and your symptoms will run away soon. B12 deficiency is more common in pure vegetarians, because B12 is only present in animal food and milk products. Hope this will help you to get your health better.