repentance

what is repentance? is it just being sorry for what you've done or is there more to it then that?
when i was catholic and went to confession we were expected to say all the things we had done wrong, feel true sorrow for what we had done then ask for forgiveness.the priest would give absolution but penance was also required to prove you were truly sorry, kind of like going the extra mile.
people would find it hard to believe but i have always felt sorry for Judas,some would think he was a terrible person for betraying Jesus and then hanging himself,in my mind Jesus picked him because he understood Judas make up and character that the temptation would be hardest on him to deal with and the prophecy would, most likely, be fulfilled.the point i think i missed was that although Judas was sorry he was not repentive trying to make amends for what he did,yes he took the silver back then plunged into a deep despair but he did not understand he could get out of this hell by asking God for forgiveness and making thing right with the other apostles.he became judge,jury and executioner of himself,he didn't turn to God or to the others.
St.Peter on the other hand,who denied Christ three times,was also in fear,despair and sorrow.he locked himself away knowing what he did was wrong. so what made these two apostles different?why was one saved and the other not?Peter did not end his life,he must have learned something from Jesus teaching that Judas missed.the fact that Peter tried to stay with the other apostles and face what had happened gave him the opportunity,that Judas missed,of getting to see Jesus after the Resurrection.Peter was sorry for what he did then Jesus forgave him three times going on to make him a great leader.If Judas had stayed around, united with the other apostles and also waited for Jesus return maybe he too would have been remembered for being a great leader.
God seems to like to work with damaged goods.he does not expect us to be perfect we are like a duel personality and sinning is just easier then resisting.He understands this but he also wants us to understand that when we do something wrong we are to tell him,understand why it was wrong, then go make it right.that's forgiveness. its a way for us to start over and not have to carry the burden of sin with us forever allowing us the freedom to do Gods' will.