Just now when I went to make something from my art library, everything in that folder is gone. I have a black circle with a line through it where all my art files were. I tried to load again from the art library, but nothing is loading. Is there anything I can do to get them back?
This is known occurrence. Search the forum and you will find several topics on the subject.
I suggest you start with this one, which is what I found in a quick search.