Technically, but not all sins. There are two types of sins, mortal and venial. Venial sins, you don't need to worry about, as these sins you do without realizing. Mortal sins, however, are done with your consent and you know that this act will hurt your relationship with God. Once you are repentant, the Sacrament of Confession allows you to cleanse yourself of these sins, with penance done to show you are sorry for your sins.