What should I do to return to Allah after falling into sins and losing faith and trust?

Repentance is obligatory and always open, and Allah rejoices at the repentance of His servant. To avoid falling into indecency again, you must do the following:

1. Remember the punishment for indecency in this world and the hereafter. 2. Persist in supplicating to Allah to divert prohibited desires from you. 3. Completely distance yourself from bad company and places where disobedience is practiced. 4. Seek righteous companionship that helps you remain steadfast. 5. Initiate marriage, and if you are unable, then increase fasting, which curbs the intensity of desires.

Renew your repentance and make up for the prayers and fasts you have missed.