Vitamin B12 Deficiency and Migraine Cerebral Torque Why Do I Feel Worse After My B12 Injection? Understanding Post Injecti Oxford Origins Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa How Dangerous Are High Vitamin B12 Levels? The People's Pharmacy Vitamin B12 deficiency, sometimes called cobalamin deficiency, happens when your body is either not getting enough or not absorbing enough vitamin B12 from the foods you eat. Vitamin B12 is an important