1- Remember that Allah gives you a completely new sheet when you repent. Don’t doubt His mercy. Yes be determined to never commit the sin again but don’t doubt his mercy.
2- Compensate for the feeling of guilt that you have by doing more good deeds. It helps
3- Read the 15 Munajat of Imam Zainul Abidin (a), preferably one each night.
4- I recommend seeing this lecture: