Our passions and feelings ought to move with reason, but since the Fall, they don’t. This consequence is not going to be fixed until the end. Of course, Jesus was appropriate in his feelings, but we often aren’t. There is no requirement that we command our feelings in perfect integrity (wholeness). So, for confession, it is not required that we suddenly have perfect control and in some way be able to summon up enough *feeling *of sorrow on command. Of course, we must be contrite in our heart, and we must *will or intend *not to do it again.
Perhaps you could read the article in the CCC about our passions. (around 1762). But they don’t talk about original sin there.
You could also look at it that you are not required to be “fixed” before confession (the penitent typically lacks sanctifying grace, for example). People who come there are broken, not fixed. Even after confession, usually some temporal consequences of sin remain in our life. We will have inappropriate attachments, responses, etc.