I've had no sales since the 18th. It isn't that they disappeard - they were never reported. I'm not exactly a best seller so it could just be me, though it's never happened before.
It's not just you. No one's sales have been updated since the 19th. This is the second time this month. The currently philosophy is to make sure that you take a screen shot of your sales every evening so that you can compare it to what Nook reports when they finally get the system working.
It isn't just the reporting. People have also been unable to upload manuscripts, etc.