ipad passcode suddenly stopped working (why?) and I dont have backups

my passcode stopped working in the middle of just sitting on my desk, charging on the electric outltet, with the Ipad on. Very odd. Keeps disabling me when I enter it. It's the right one I have used many times.

BUT I don't have a backup on itunes -- or at least one very current. And I dont know if the auto backup is very current as I only started reusing the Ipad today.

1)why would the passcode change ??? hacked ??

2)what to do to get back my ipad? no itunes backup, and find iphone for icloud does not find ipad as it thinks it is off!!