It had gotten corrupted..
Fortunately I have a backup.
I'll add the map back in some time today.
EDIT: Was super busy on the 10th so I couldn't get on my computer..
Was busy today(11th), I thought I had a backup but it was just a new map that I renamed to Beta for testing server plugins.......
Which means yet another World lost due to corruption/glitches and/or plugins....I have no idea how they keep getting corrupted...
Also, depending on the issue, sometimes you can remove entities from the map using a tool like pymclevel. I've used that technique to fix our map a couple of times when minecart antics took it out.