All you can do is apologize, then stand back for a while to let the steam boil off or the irritation heal over. You can't just go from being pissed off and reacting to laughing about the dumb things you did/said without a bunch of time in between.

The only thing you can do to prevent future occurences is to pay attention to when it starts happening. Let the guilt give you a reason to plan for how you'll deal with anger in the future, then let it go. Maybe you can tell when you're beginning to get pissed off and nip it in the bud or walk away before you do something about it.

Maybe you're beating yourself up over something others have barely noticed. THAT happens too, especially in those with Type A consciences. In this case, your anger-based words and actions aren't the heart of the problem. The problem is that you feel guilty for becoming angry and reacting to anger as any normal person would. Daylia, in the 4th post to this thread, talked about treating yourself with the same kindness as you'd treat another person. What advice would you give another person if they asked what you've asked?

In simple terms, let the person you feel you wronged decide what moral penalty they're gonna impose. If they say "Aw, forget it already," then you have to forget it already.