My TOC appears to have gone "AWOL." I was creating folders in my project files and moving documents around within RH when I got a message that said something like, "(Project Name) Default has been changed outside RH" and then something about "would i like to update the project with that change." Since I had no idea what that change was, since i was IN RH at the time and certainly didn't do anything intentionally outside RH, i declined making this change. And the next thing i knew, the TOC I had been looking at, was gone.

I've closed out of RH, i've rebooted my machine, nothing. I have not recompiled, however... Is there something i can do to get the TOC back without having to do it all over again?

Do you have a backup of the project? With the project closed, you could copy the HHC file from the backup. I would take a backup of the project first so that if anything goes wrong, you are no worse off than you are now.