If you keep falling back into old habits, there is hope in Jesus Christ.
Sometimes we will want to be a good person and do good things, but at the end of the day we feel like a terrible person. We failed to do anything that we wanted to do and immediately fell back into our old habits.
We might even feel enslaved to our sins, constantly returning to them even when we are trying to break free from them. At times we are even tempted to give up the struggle and just be content with our bad choices.
The good news is that we can be set free from our pattern of sin and experience the joy of Gospel living. The key is to let God into our lives and to let him work miracles in our heart.
Here is a prayer by Fulbert of Chartes that can act as a first step in the right direction, prayed each day for the intention of being set free from a sinful life. Then, through the confession of our sins in the sacrament of Penance, we can experience the love and mercy of God in a new way.
Jesus Christ, the beginning and the end, the resurrection and the life, the perfect man who gave His life for sinners, I worship you, I adore you, I sing aloud your name. I am one of those whom you saved, whom you set free, when you died on the cross. You redeemed me from the slavery of sin. And yet I cannot escape the over-powering sense that I am still a wretched sinner, that my every action is worthless or evil. I am like the dry sand of a desert thirsting for water. I am like a criminal languishing in prison. Good people try to help me, and I pray that you will reward them; but their goodness does nothing to assuage my sense of wickedness. Patient people try to teach me your ways; but I am so stubborn that I cannot learn. Humble people seek to serve me; but in my pride I cannot truly appreciate their services. Lift the burden of wickedness; break down my stubbornness; root out my pride. Let me receive your life-giving love. Let me be free.