When a fellow believer tells me how disenchanted and depressed they feel because they fell and did some bad things or don't even seem to have a heart for God anymore, I hope I can always remember to tell them this:
"Cheer up. You're much worse than you think."
The only thing that happened is that you discovered a little more of what already resides in your heart. But God has seen it all the whole time and still delivered up His Son for you.
The power of the Gospel is not in it's ability to make us feel good about ourselves or minimize our sin. It is in its ability to slay the old Adam with the truth of our foolish condition and create in us a man of faith, who doesn't live for himself but for Him who died and rose from the dead for him.