I know how you feel, I have been there and sometimes I still feel that way. I guess for me it is helpful to remember that Satan and his demons are always trying to take our souls and Saint Padre Pio said that the devil is like a barking dog on a chain, he can bark and bark but he can’t hurt us unless we get into his area. Saint Josemaria Escriva said that no matter what we feel don’t consent to it, even if it is the most horrible thought as long as we don’t consent then God is happy with us. It is good if we feel constant temptations because that means that the devil doesn’t have us, those whom he has he doesn’t need to tempt because the devil already has them.
For me the best things that slowly makes the constant sin in my life slowly go away (and the thoughts on sin and temptations will always be there, that is just part of human life) is to have a regimented prayer life. Prayer is a very powerful weapon (as a matter of fact St. Padre Pio used to call his Rosary his weapon). Remember that we are always at war, life is a war and prayer is the best defense against the devil. My daily prayer routine is these 4 things, you can use it if you’d like or come up with something that you like on your own. 1) I say the morning and evening prayers of the Liturgy of the Hours. If you want to do this I recommend getting the prayer book called Shorter Christian Prayer. 2) I say a daily Rosary. You can mention all of your intentions before praying the Rosary and offer them up with your Rosary. 3) I contemplatively read the Bible for at least 20 mins a day. I also recommend the book called My daily Catholic Bible because it’s 20 min daily readings of the Bible. 4) I do all of my work for God and I offer my whole day up to God. This includes work while at work and all of your daily chores at home.
I also recommend saying the Jesus Prayer whenever you feel tempted. the Jesus Prayer is short and easy to memorize. This is the Jesus prayer, “Lord Jesus Christ, Son of God, have mercy on me a sinner.”
Also read about the Saints, it’ll motivate you to lead a good life. You can also get a Benedictine Jubilee medal, it wards off evil spirits, and is sometimes used during exorcisms because of it’s power to ward off evil. Just have it blessed by a priest in the recommended fashion, you can find how to bless a Benedictine Jubilee medal online. Basically, they ask for the intercession of St. Benedict, say a short exorcism prayer and bless it.
I hope this helps. God bless.