Vitamin B12 deficiency can cause symptoms like headaches, fatigue, depressive mood, gastrointestinal issues, and more. While vegetarians are at a higher risk of vitamin B12 deficiency, it can affect non vegetarians too. Check Why Do I Feel Worse After My B12 Injection? Understanding Post Injecti Oxford Origins Headache After B12 Shot: 3 Effective Strategies to Feel Better Vitamin B12 Injections: Vital Therapy for Pernicious Anemia How IV Therapy & Vitamin Injections Help Headaches SparkHealth