World not saved

I had a world saved and played like 2hours a day for like a week but last night at like 11pm I stopped playing and put my laptop on sleep and went to bed, the next morning my alarm rang on my laptop and I was tired and too lazy to log in so I just pressed and hold the power button till it shut down, later that day I tried to play the same world but it wasn't in the world list. Is this a glitch or bug or was it just my fault?