At some point in our lives we all realize that we feel bad for the things we have done. I have been there and so have many many others. The answer can only be found when you realize that you are forgiven, because of the sacrifice that Christ made for you on the cross. He stepped in and paid for the penalty that our sin causes. Rest in the grace that He freely gave to you.
1 John 1:9 (New International Version)
"If we confess our sins, He is faithful and just and will forgive us our sins and purify us from all unrighteousness"
This passage is talking about confession to God using Christ. God will forgive us as long as we confess to Him that we are in the wrong, but do not let guilt get the better of you. Guilt is a trick that Satan can use to keep you separated from the love of God.
1Therefore, since we have been justified through faith, we[a]have peace with God through our Lord Jesus Christ, 2through whom we have gained access by faith into this grace in which we now stand. And we[b] rejoice in the hope of the glory of God. 3Not only so, but we[c] also rejoice in our sufferings, because we know that suffering produces perseverance; 4perseverance, character; and character, hope. 5And hope does not disappoint us, because God has poured out his love into our hearts by the Holy Spirit, whom he has given us.
6You see, at just the right time, when we were still powerless, Christ died for the ungodly. 7Very rarely will anyone die for a righteous man, though for a good man someone might possibly dare to die. 8But God demonstrates his own love for us in this: While we were still sinners, Christ died for us.