I've been taking Vitamin B injections once a month (for four months now) from one of my doctors. She said they would give me "a lot of energy" but I get extremely sleepy and tired, which lasts for hours, after receiving the injection. The day after I usually feel energetic and good. I had an injection yesterday and had to fight to stay awake on the drive home from her office.
I told the doctor about this and she was surprised but is continuing the injections. So I was wondering if anyone else has taken these injections and had the same reaction.