Minecraft crash

I just started up my new survival world and went mining the new ores look amazing, i got some iron smelted and builded myself in a mountain because it was night, when half smelting was done, my game crashed, i was confused opened up minecraft again, smelted all the iron and the game crashed once again. I went into spectator mode because i thought i could be warden, i dont think my pc would handle that so i went to search the caves, i saw a water cave and then like all the water dissapeared and crashed my game ONCE AGAin.