While repentance does involve feeling sorry for your sin but that is not the entirety of it. What does it mean to repent? As the Greek word for repent is metanoneia, it means to have a change in mind that begets a change in purpose. It means that if you repent of your sins, it makes you change your mind about your sins and it results in having a change in purpose not to live in sin. Judas Iscariot may have felt sorry for his betrayal but he never repented towards Christ for forgiveness. What he did was not unforgivable but he chose to commit suicide instead.
Many people confuse repentance with regret. While repentance does involve some regret but having regret does not necessarily mean the person has repented. Let us take a cookie jar scenario. You regret you stole the cookie because you got punished. If you repent of the act, it is because you see that stealing is wrong and offensive. You realize that whether you get caught or not, it is still wrong and it leads you not to repeat the same offense as a result of that repentance.
So have you really repented of your sins or are you just indulging in self-pity?