When we think of sin, we don't think of the extreme circumstance. We don't think about the consequences that entail until afterwards, when we have that nawing feeling that something isn't right when we go before the Father.
Its because when we choose to sin, we forget the promises we have when we are walking in His Kingdom. We forget about all that God has given us, and in the same sense forget Him. And He turns His back on us for a time until we are ready to repent, because He cannot look at our sin. But, He doesn't forget us.
When we repent, He remembers only who we are in Him. He doesn't remember the sin. We might remember but we aren't to with any confiction as its been taken care of and we are in freedom.
A good example of what happens is in Zech 3:1-5. Zechariah sees a vision of Joshua standing before the Angel of the Lord and satan is on his right side to oppose him. All Joshua sees is the eyes of the Angel of the Lord, and can't hear a word that satan is telling him. Joshua in his fithly dirty rags is standing before the King of Kings and looking at Him while the King asks for a clean clothes and a turban for his head.
Before this, the Lord turns to satan and rebukes him. satan has no legs to stand on, no accusations to put forth for the King of Kings had thrown them as far as the eyes could see. They are no more in the eyes of the King.
So when you are feeling like you haven't done enough after you've repented, read Zech 3:1-5. Look in the eyes of the Lord, and satan will have no ground to stand on.