I'm a cheat and a loser
That seems harsh. Why do you feel like a cheat and a loser?
Because I have committed a serious crime
It's understandable that you feel bad after doing something that you know was wrong.  If you can, find a way to fix the damage that you might have caused, or even turn yourself in to the police.
I would never see the light of day again.
If your crime is severe its good to atone for it, no matter what the punishment may be. That way you can show how truly sorry you are and fix your past mistakes.