World dissapearing

My world creating (building and mining) was all deleted when i was gonna play on the world. An enderman killed me instantly when i spawned but when i respawned i saw that my house, my fence, my farm and my mine was all deleted like if it was never built. This was weird and i am so angry becouse my mine was with wooden stairs on both roof and floor and oak planks on the walls. I was so angry becouse that was several days of hard work in Hard mode and it was my first time ever playing on Hard so i am both mad and sad. Happend a single day after my birthday. ._. Got fixed about half a day later at 7 PM in norway and i found this error about 9 AM.