When you feel guilty about something you have done or feel mad about something that someone has done to you, you can think about the situation and picture it in your mind and then say, "I chose wrongly there because I am not at peace. I want to choose again. Holy Spirit, please decide for God for me in that situation and undo any damage or harm that was caused from my decision."
Have you tried this? I would be interested to see if you have. I have been doing this and it is working.