Server crashed once and is acting up, any way to fix this?

Hi, I was hosting a local server when I had a power outage. When we got back to playing, it has reset one of the players back to level 1, and the whole server back to day 1 from day 33ish. The other characters had no other problems, but there seems to be a lot of issues still happening server side. Everything goes really dark randomly, and makes it very hard to see, and there is a lot of frame skipping and freezing now. Has anyone else had this issue? Is there any way to fix it?

Thanks in advance.