iPhone Deleted All Data ITSELFFF???

Hey im new to the forum

Heres the story..

I was sound asleep this morning.. I wake up to look in my pocket for my phone an its not there. I ask the Mrs and she says its in the living room as she was looking at it to see who i have texts from to be nosey although she knows it has a 4 digit pin lock on it and she doesnt know what it is

I asked for it back and she said yes but it lookd weird. Indeed it did look weird because Messages - gone, Apps - gone, Pictures and Videos - gone, It had basically been reset to factory settings.

I recently 2 days ago updated to 4.2 so have a back up on the PC. Hopefully this will work. It is doing it now. She claims it did it itself. Is this even possible? Or is it what i have assumed... 4.2 has reset the setting that erases all data after getting the pin wrong number of times? If it IS deleting itself (which I doubt) then this is something I need to fix.

Thanks

Chris