I'm My Own Worst Enemy...

I've screwed up big time, and even though I've been forgiven, I wake up every morning and flog myself emotionally... "How could I have been so unlike myself? How could I have been so inconsiderate? How could I have been so antagonistic?  How could I have been so selfish?"  Every time I think about it, I feel sick... I feel like the worst person on the face of the planet... It makes me want to cry every time I think about it... I need to find a way to forgive myself, but again its the morning... I feel like throwing up and crying again... I can't believe myself.. how could've I let myself become this monster?  I've changed  for the better because of it but it terrifies me that I might have caused too much damage... Blah! again with the sick and weepy feelings... :( How do I fix me?