Dedicated Server - Characters despawned upon closing the server.

Server: It's a password protected dedicated server, with me and a couple of friends. The world setting is all default. We have two mods on - Global Position and Simple Health Bar.

YESTERDAY: My friends and I disconnected from the server around Day 65. We just came out of caves, before we disconnected. Then, I shutdown the server for the night. 

TODAY: The game is still at Day 65. However, we are all back in character select. We lost our map progress and our prototype progress as well. And it says "Day 1" for us. This is the first time this happened with my dedicated servers. I am not sure if we also lost our items (that were in our inventory before we disconnected yesterday) or they are all dropped somewhere in the caves. 

EDIT: We lost our items that were in our inventory from the first year. Backtracked our path and did not find our items.