Need to figure out how to get to an earlier saved "state" of iTunes

I accidentally renamed a chunk of song files in my iTunes library so that they are now jumbled together. I want to go back to the state that my iTunes library was in about a half-hour prior to that edit to remedy it, but when I try to do so, it gives me an alert saying "The item "iTunes" can't be copied because there isn't enough free space"

How can I go back to my earlier version of iTunes - do I need to delete it all and redo it? I'm stuck!