I had a similar issue the other day, and I've had it before, but this time I forgot to create a back up folder because I just started playing again.
I have a dedicated server running on my PC and we lost power for a moment and I think it corrupted some of the server world files. This happened before but the world wouldnt even load, but this time it loaded but the trees were missing, the terrain texture was like flat grey, and my character seemed to be reset. I assumed it has something to do with the server not saving correctly. I havent found a fix other than to make sure I back up the world and character files incase the power goes out.
So I ended up starting a new game and just used the console to increase my level to the same level I was and spawned in some of the items I know I had. I wasn't trying to cheat, I was just trying to resume where I was prior to the crash. Unfortunately, the base was obviously lost so like I said, I just tried to spawn in some items to "resume" the game that crashed.
It kinda sucks, but its better than starting at level 1 again.