Yes, I've struggled with very similar feelings about guilt over past misdeeds. I agree that feelings of guilt serve a critical function in modifying our future behavior such that we never do the actions that lead to us feeling guilty in the present moment.
However, those feelings of guilt become dysfunctional after we've learned our lesson. After we experience guilt, and resolve never to do again what caused the feelings of guilt, then we can let those feelings go - they've done their job. If they keep coming back, there exist practices which can take us deeper to reveal the obfuscated reasons for their recurrence. No reason to keep torturing one's self after the lesson has been learned.
However, those feelings of guilt become dysfunctional after we've learned our lesson. After we experience guilt, and resolve never to do again what caused the feelings of guilt, then we can let those feelings go - they've done their job. If they keep coming back, there exist practices which can take us deeper to reveal the obfuscated reasons for their recurrence. No reason to keep torturing one's self after the lesson has been learned.