Today when I logged on i found that everything I had done yesterday was completely undone. I spent probably 8 hours in the mining world collecting all kinds of goodies, came back planted some watermelons, some pumpkins, and had 3 double chests filled with stuff. Today I am back exactly where i was yesterday at this time. Everything in my area is reverted, my chests, my inventory, and my ender chest contents, and the stars i got for voting. what happened?

I just went to the mining world and everything i did there is still the same, so i can't re-mine the diamonds i found, or re-loot the abandoned mine shaft chests.

 

Thanks.

And no, I can tell the difference between grief/account misuse, and a rollback. nobody can undo with precision every tunnel i dug, every dirt block i planted, and return my ender chest, and my inventory, and my normal chests to the exact contents and layout they were in 20 hours ago. I know for a fact where I left off last night, because I was standing in the field i had planted waiting for stuff to grow watching hulu when i nodded off in my chair. I woke back up to a message saying the server was restarting and would be back soon, said to myself that i should be going to bed anyway, and turned the game off.