Padre Pio had wise advise concerning this to his Spiritual Children. He advised them ,after having fallen into sin simply to repent dust themselves down and get into action again without a backward glance. Anything else coming from the evil one. I recall a vision of Jesus a very holy French nun had and she started at once to apologise for a sin she had committed. Jesus looked at her blankly with no idea what she was talking about. He went on to explain that sins confessed in confession were wiped clean. As though they never existed. He not only forgave but totally forgot. When St Paul in Romans informs us that for those who love God all things work together for the good, He really does mean ALL things ,even our sins. Thus even our sins serve for our sanctification. Only God could do this.