How do you deal with the shame after a rage blackout?

Hello, I (21F), just had to become suddenly and forcefully self aware of how unmanaged my BPD has become. I have severe and chronic ADHD that my parents left untreated and unmedicated until I was in college when they became insistent on medicating me despite me not wanting it at that point. However, recently I was slightly manic, and aware of such, and was hanging out with some friends and drinking. The rest is what I have to go off of their story. They claim I was violent and aggressive, which I don’t doubt internally could come out, but never, ever had before. I don’t remember a thing. I’ve tried everything to remember anything but I don’t, but I do remember “waking up” and coming out of the rage blackout, and I know for a fact it was not the alcohol that caused this much of a blackout, this is the thing that I’m stuck on.

My family and friends are not acquainted with understanding mental illness well, especially not BPD, and I can only feel shame and excessive sadness for what happened and I’ve lost all relationships in my life from this one night. From those who maybe have been through this, or maybe something similar to this- How do you deal with the aftermath? How do you make peace for something you can’t even understand that you actually did?