The Act of Contrition is a Catholic prayer that is used during confession. It is basically a pledge between the confessor and God, where the person confessing expresses sorrow for his or her sins, and promises to behave better in the future. There are some versions which are more popular than others, but there is no specific right or wrong version. In fact, when I went to confession as a child, I was encouraged just to speak from my heart if I was unable to remember one of the versions I was taught.
Here is a popular version in the original Latin:
Deus meus, ex toto corde paenitet me omnium meorum peccatorum
eaque detestor, quia peccando,
non solum poenas a te iuste statutas promeritus sum,
sed praesertim quia offendi te,
summum bonum, ac dignum qui super omnia diligaris.
Ideo firmiter propono,
adiuvante gratia tua,
de cetero me non peccatorum peccandique occasiones proximas fugiturum.
In English, this is basically translated as:
O my God, I repent of all my sins with all of my heart
I detest them, because by sinning,
Not only did I have gained just punishment from you,
but most of all because they offend Thee,
the highest good, who is deserving of all my love.
I firmly resolve with Your help,
to avoid the occasions of sin.
The Act of Contrition for children, which is the one I learned as I prepared for my First Holy Communion, is short and sweet: "O my God, I am sorry for all my sins because they displease you, who are
all good and deserving of all my love. With your help I will sin no
My mother was taught this one when she was a child: "O my God, I am heartily sorry for having offended Thee, and I detest all
my sins, because of thy just punishments, but most of all because they
offend Thee, my God, Who are all-good and deserving of all my love. I
firmly resolve, with the help of Thy grace, to sin no more and to avoid
the near occasion of sin. Amen."
You do not need to be Catholic, or indeed even Christian, to declare an act of contrition. If you are Catholic, you can use the prayers above, or if not, just speak from your heart to the deity of your choice or to the universe itself. This can be a wonderfully cleansing and uplifting practice to help
switch you onto the right track, to avoid things that are unhealthy or
negative for you, and to move on in a more positive direction.