My world got reset and there are holes

I was going to get on my world to put in some more work on it. When I joined the world it the game said I died and that my bed has been destructed. Keep in mind I've had this world since January and got on almost everyday. Everything is gone and the world looks like how it was when I first started. Then I did a little bit more exploring to the area where I was going to make another build and there where holes going all the way down to the void. So my world has been completely reset and all my hard work is gone. I am frustrated, furious, and distraught. I really love Minecraft but I'm really mad about this.