I doubt that your /home "has gone for good" and suspect that what you are seeing is much more innocent than that. I don't know what you actually did in detail to mount the ISO file, but I imagine it was something like
I think that if you unmount the ISO file your /home will appear again.
sudo mount -o loop -t iso9660 path/to/file.iso /mount/path
If you don't know exactly what you did in terminal you can find all your old commands by using the "up cursor key" to go through the history. That should show you where you mounted the ISO, and may help to unmount it again.
sudo umount /mount/path
In future you do not need to mess around in the terminal to mount an ISO file, you can either open it with Archive manager, or Archive mounter. On my system ISO files are opened by default in the archive manager, but a right click on the file shows archiove mounter as an alternative.