The first person you probably have not forgiven is yourself. More people have a lack of forgiveness toward themselves than toward anybody else. They are unwilling to forgive themselves and to recognize that God says, "As far as the east is from the west, so far has He removed our transgressions from us" (Psalm 103:12). If you are a believer, He has already cleansed your conscience from dead works so that you might serve the living God. God cleanses us for service in order to not leave us with the guilt of past sin. That should be dead, buried, and forgotten.