Some of the things that make me cringe happened 30 years ago. The shame is just a twinge though. Time has eased the shame. I don't dwell on it.
You are three days sober, so the past is going to be pretty raw. All I can say is don't get fixated on the past. Remorse is normal in early recovery. You can't change the past, but you don't have to be doomed to repeat it. Staying sober is the redemptive act you can do to make peace with your regrets.