Is this ever going to get better I'm losing hope . I felt awful the week before my b12 injection which was last week . Very down and exhausted . It wrote a post re the way I was feeling . I had my injection 10 days ago and ha e felt no better since . In fact worse . I feel run down actually . I am more exhausted than I was and have a painful mouth ulcer and cold sore now today . I feel floaty and weak and anxious and depressed and very scared that the injection that gave me a glimpse of the former me has stopped working .