it's a long shot but perhaps you pressed some keys in your sleep? Try locking the watch before bed and see if that cures it? Alternatively, try a hard reset just in case the watch got its knickers in a twist.
I rebooted the watch (shut off then on) yesterday and it didn't happen last night. It was still on do not disturb when I woke up this morning. Hopefully it just needed a reset.
so one thing I have seen is the DnD icon (the moon) still to be showing after DnD/Sleep time is over. This doesn't mean DnD is not off (I believe its a screen refresh issue), I believe you should still get notifications. Easiest way to check is send an email to yourself after Sleep time has ended to check.
