I was playing the minecraft windows 10 edition then my pc restart itself and i couldn't save the world then my pc finished the update and i log in the my account then i saw my world was deleted and i shocked. I am really upset. PLEASE HELP ME

I was playing the minecraft windows 10 edition then my pc restart itself and i couldn't save the world then my pc finished the update and i log in the my account then i saw my world was deleted and i shocked. I am really upset. PLEASE HELP ME!! I am gonna cry in my bed please help