What has happened is even though you have been forgiven, you haven’t forgiven yourself. There are many who go through this. I was told that to think of going back to confession just because I don’t feel forgiven would be a direct insult to Jesus.
There are many reasons we don’t forgive ourselves, from a lack of trust in God, or belief that he can’t heal and forgive you. It could be pride or a lack of love for ourselves, scrupulosity. We are a broken people, we need to remember that Jesus told the Apostles whatever you forgive on earth will be forgiven in heaven… Believe it, even if you don’t feel it.
I think that most everyone still feel regret for past sins and it sometimes takes alot of time and prayer to heal from the wrongs we’ve done to ourselves or others and especially to God. When a particular sin niggles at me, I’ve found that praying the prayer below helps me. I hope that it will be able to help you as well.
Prayer for Reparation of Sins
[from a Poor Clare nun]
Eternal Father, I offer Thee the Sacred Heart of Jesus, with all its love, all its sufferings and all its merits.
First … To expiate all the sins I have committed this day and during all my life.
Glory be to the Father, and to the Son, and to the Holy Spirit,
as it was in the beginning, is now, and ever shall be, world without end. Amen.
Second … To purify the good I have done poorly this day and during all my life.
Glory be to the Father, and to the Son, and to the Holy Spirit,
as it was in the beginning, is now, and ever shall be, world without end. Amen.
Third … To supply for the good I ought to have done, and that I have neglected this day and all my life.