I got a typo when one of the words was "n't" and i selected it for not I still got it right but still
So 'y'all are not sad?' is supposedly wrong. When I learnt Spanish, y'all was a word in English.
If you say it in the US it's considered Southern, but I'm born & raised in the north and I use it too. It's just so useful since thou and thee aren't used... You could just say everyone, but y'all works casually... No one blinks when I use it.