I don't blame you at all for being angry in every direction. Sounds like a horrible shock. I think it's a case of everyone and no one is a bit to blame and I don't think there's much point in beating yourself up or the school.
You've done the right thing, making see she's seen the right reaction happen and you need to keep enduring she gets the right life lesson.
Honestly, I can remember times when we were hysterical with laughter, literally! Proper crying years down cheeks gasping for breath and clutching stomach, especially in gcse German lessons for some reason. And that was without alcohol. I also started to bunk off lessons and no one ever noticed. Teens are clever and school is their home territory, they know the culture and rules and boundaries and pretty much every routine and brick of the place. If you're not under suspicion, it's very easy to get away with out ragelus things.
So I think it would not be the first thing that comes to mind for a teacher, especially if she's a quiet studious type normally.
So, go easy on yourself and the school, go hard on her, at the same time try and reconnect with her and get engaged with her life so you aren't caught out next time/ for a while.
Honestly, it's awful, but it's also the stuff of looking back and laughing and say, 'lord, you were a horror at school!' ...