Vitamin B12 levels low? My patient would get a headache every morning, not knowing it was a red flag for deficiency B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Vitamin B12 Injection Dosage Duluth GA Anns Therapies Is trained and fully insured in B12 injections for wellbeing. B12 deficiency has been linked to the following signs and symptoms, Extreme tiredness. Feeling faint or dizzy. Breathlesness. Headaches. Pale B12 Injections: Who Should Get Them and How Long Do They Last?