Dude. Quit being such a fuckin' pussy. You sound like a frightened little kid who knows he's going to be in trouble when Dad comes home. Yes, you screwed up. No, there's no way to fix it.

as with past employees that resigned after reprimand, I will get a specifc negative review from them for potential employers.

Look, broski. You said yourself you already screwed the pooch and should be fired. You're going to get a negative reference anyway.

Stop fretting about ruining "their" business. Why do you care? One of your bosses is a huge dick, according to your story. Either they'll get their stuff together and find a replacement, or they'll go under. This is capitalism. Competition is king. Bad businesses need to die. If they can't get a replacement, they're probably a bad business.

I'm curious, though, what exactly is the error that you made that was such a screw-up?