Against my conscience

Two days ago, I suddenly have a urge to do something bad, or rather against my conscience. (Yes, I did it and tried to pretend nothing happened).
I just want to know how it feels... Because my way of learning involves doing it or actually been through it (at least most of the time).
Damn!! It's feel damn bad... two days after, I still feel so guilty.
I am sure that most people had heard that doing good deeds might not have good return...but now, I think at least it gave us a good conscience and not to lose sleep over it.
Ok, what I done is not terribly bad (I think); but at least it is bad enough to make me feel really lousy. Guess I have to make it up in other ways...
Conclusion: Do whatever I think is right and not against conscience anymore.