Lost Entire World after game froze then crashed

After I received the newest update {Aqua Update}, I was playing in my world and the game started to glitch really bad while jumping, running and or killing mobs. So I kept playing through the glitches until it became so bad that it froze. After which I tried to shut the game down to restart. It would not allow me to do anything so I used control alt delete command to get the task manager to shut it down that way but I couldn't get that to come up so I had to just hard restart my machine. After which I turned the machine back on and restarted the game. I then had to sign back in and found that my entire world had been deleted. Seriously upset about that because I have been working on it for like months and months.