Feeling constantly tired, foggy, or run down? Vitamin B12 plays a key role in energy production and nervous system health and low levels can lead to fatigue, brain fog, and weakness. Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa Vitamin B 12 Injection Mobile and Clinic IV Therapy ASAP IVs IV Hydration Experts of San Diego, Phoenix, Scottsdale, San Francisco I am tired, I am 3 months into the treatment and constant pushing is killing me when does it get easier : r B12_Deficiency