Is the doubt that averts the Hadd penalty considered one of the major sins?

What happened is not Zina (unlawful sexual intercourse) necessitating a Hadd (prescribed punishment), but rather it is among the minor sins that are expiated by avoiding major sins. It has been reported from the Prophet, peace and blessings be upon him, that good deeds efface evil deeds. As long as the questioner has repented with sincere repentance (Tawbah Nasuh), her repentance is accepted, whether the sin was minor or major.