When it is painful to remember the past, it is better to simply repent of what had been bad, and think no more about it. In order not to despair or be enfeebled by it, 'remember the examples of God's great mercies to great sinners. The main thing: do not condemn, do not envy, know yourself and be with God.'
The grace of repentance, which acts in those who struggle, is a patristic inheritance. It is a divine transaction and exchange in which we give dust and receive heaven. We exchange matter for the Spirit. Every drop of sweat, every pain, every ascesis for God is an exchange.
In words of boastfulness and self-justification there always lie concealed contrariness and pride, from which God turns away. After sinning one ought immediately to 'flee.' But, you will say, where? To the calm haven of heartfelt repentance. Every night before you go to sleep, tell God, the Knower of Hearts, all the sins you have committed in deed, word, and thought, and believe that God receives your heartfelt repentance. At the same time try to render your heart contrite by the memory of sudden death.
Sorrow over your sins makes you as gentle and meek as a lamb; and where there is meekness and gentleness, there is serenity and beatitude. What is more precious and blessed than spiritual calm?
By holy baptism original sin is expunged, as also sins committed before baptism. It also eliminates the violent power sin has over us till rebirth; it gives us the grace of the Holy Spirit by which we are united with God in Christ, and we receive power to subdue and conquer sin. For the simple reason that we are not delivered from the struggle with sin, we cannot be entirely free from sin during the whole of our earthly life, and even the righteous man may fall seven times (i.e. often) and rise again by repentance, says Scripture (Prov. 24:16). He falls on account of his weakness and limitations, because he does not always notice sin which subtly and imperceptibly rears its head from his fallen nature, and which is artfully and imperceptibly offered and suggested by fallen spirits. Repentance becomes his secure possession, his constant weapon, his invaluable treasure. By repentance the righteous man maintains his fellowship with Christ. He is healed by repentance from the wounds caused by sin.
Faith is truly a gift, gained for us through Christ's advent. But this does not abolish our freedom or responsibility. God desires of us not only faith but action too.
Repentance is the renewal of baptism. Repentance is a contract with God for a second life. A penitent is a buyer of humility. Repentance is constant distrust of bodily comfort. Repentance is self-condemning reflection, and carefree self-care. Repentance is the daughter of hope and the renunciation of despair.
There is nothing impossible unto those who believe; lively and unshaken faith can accomplish great miracles in the twinkling of an eye. Besides, even without our sincere and firm faith, miracles are accomplished, such as the miracles of the sacraments; for God's Mystery is always accomplished, even though we were incredulous or unbelieving at the time of its celebration. 'Shall their unbelief make the faith of God without effect?' (Rom. 3:3). Our wickedness shall not overpower the unspeakable goodness and mercy of God; our dullness shall not overpower God's wisdom, nor our infirmity God's omnipotence.
If the main goal of the repentant sinner should be total, light-bearing and blessed communion with God, then the main hindrance to this is the existence of the passions still active and working in him - the virtues being as yet unsealed in him - and the unrighteousness of his powers. Therefore his main work upon conversion and repentance should be the uprooting of the passions and sealing the virtues - in a word, correcting himself.
Someone may say: 'I have faith, and faith suffices for salvation.' St. James gives him the answer: 'Even the demons believe, and shudder. Faith without works is dead.' (James 2:17-19)
What does spoil repentance is being again entangled in the same evils. 'For there is one' we read, 'who builds, and one who pulls down, what have they gained more than toil? He who is dipped in water because of contact with a dead body, and then touches it again, what has he gained by his washing?' Even so if a man fasts because of his sins, and goes his way again, and does the same things, who will hear his prayer? And again we read 'if a man goes back from righteousness to sin the Lord will prepare him for the sword,' and, 'as a dog when he has returned to his vomit, and become odious, so is a fool who by his wickedness has returned to his sin.'
Woe is he who knowingly chooses to sin with the intention to repent when morning comes, for he knows not what the coming day or the night that precedes it will bring.
Whoever repents sincerely is prepared to withstand any sorrow: hunger and homelessness, cold and heat, illness and poverty, humiliation and banishment, lies and slander, for the soul seeks God and does not concern itself with anything worldly, but instead prays with a clear mind.
You will not perish on account of thoughts with which you do not sympathize and from which you at least try to be freed. Only repent, & humble yourself. And God will forgive you.