I was just on my realm (which I purchased through realms plus) and had a large amount of resources in his hotbar which I had stored up over several months.  

I came to a perfect square hole in my map which had not been there before.  My friends couldn't see the hole or fall through it, so they were walking over it.  I tried walking with them, but fell in and suffocated.  My items never dropped, so I died and lost everything I had been working on for months because of the glitch. 
 
I turned it off, hoping it wouldn't save, but reopened it to find I had still lost everything, but the map was repaired and there was no longer a hole.

Is there a way to return the game to the previously saved version before the glitch took place?