Don't get me started. My mom regret is mixed with guilt and complicated grief. Short story is she was drunk, I abandoned her, and she died. Could I have done anything? Probably not. Did I need to protect myself? Probably. Do I still feel bad? Hell yes. And she passed 20 years ago. I don't know if we ever really shed the weight or just learn to live with it. I do the mindfulness thing. The memory comes up. I say there it is again. I observe it. Feel it. Remind myself to be compassionate to myself. Let it pass. Keep breathing. Move onto the next thought.