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. Why Do I Feel Worse After My B12 Injection: 6 Body Reactions Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa Feeling drained even after a full night's sleep? Your body might be craving Vitamin B12 B12 is essential for energy, focus, and overall wellness, but your body can't make Feeling tired all the time but can't figure out why? Low Vitamin B12 often shows up as just fatigue before turning into something more serious. This article explains the hidden signs, who