eat humble pie... you are going to feel horrible , nervouse etc.... just say sorry and it will not happen again. do not take off sick in a while and say it was not meant for the other people it was supposed to be to a single person.... do not name names... you are not abliged to name names at all.
but yeah... keep your cool and try to be relaxed as possible... remember.. they can not fire you for doing a stupid spam msg.... warning verbal or written but that is it
Why do people never, ever read threads.