I've been exploring a cave system, but the game has bugged out. Now, any blocks I destroy don't drop, no mobs are spawning, I can do the animation for but can't actually consume food, and if I venture too far in any direction, the map just stops, and it's a sheer drop into nothingness.
When I load up the game again for a while my character is falling and there is absolutely nothing around me.
The worse thing is, if I do anything, after a period of time I'll be warped back to where I was when I loaded up, and everything I've done since then will be undone. After this happens a few times the game quits. I once got a screen that had a long message that started by telling me my memory had ran out, however I couldn't read the rest due to the game quitting.
I don't know what caused this - my computer's got plenty of spare memory, and in game I did nothing abnormal prior to getting this bug.