Bad day in middle school... please help with advice.... :(?

Its all right. I've had it happen, too, also unintentionally. I had classes alternate daily, so I accidentally went to the wrong class, thinking it was a day it wasn't. I got a detention for skipping class, though I was in another. And don't let the teachers get to you. They like to lecture. But they do it more when you're younger just to keep you on the right track. I got worked up over it when I was your age, but looking back now I understand it affected me more than it needed to. So take it from the college kid; no point in stressing. You'll laugh at it in about a month. I know it makes for a crappy day, but you did all you could, and your a good kid to have bothered apologizing. And they get less strict when you get older. Now its just to keep you from thinking its easy enough to repeat. By the next day, there won't be more mention of it. If there is, it'll be only in joke form.