The best answer is from Allah in Quran : Say O My servants who have transgressed against themselves ( by committing evil deeds and sins) Despair not of the Mercy of Allah. Verily Allah forgives all sins. Truly He is The Oft-forgiving , The Most Merciful) Sura 39, Verse 53.
The Mercy of Allah (SWT) is much greater than our imagination. It includes every thing (My Mercy embraces everything) Sura 7, Verse 156. Special mercy is for sincere servants servants of Allah who left wrong deeds and repented and sincerely decided not to do it again. Allah Love those who repent and purify themselves. Sura 2, Verse 222.
We need to trust The Mercy of Allah and hope to receive His Oft-Forgiveness. He Has Promised every one who repents and sincerely seeks forgiveness to Grant him His Forgiveness.
'It is good to repeat (YA ARHAM ARRAHIMEEN) also to repeat (YA GHAFOUR YA RAHEEM).