If you freaked out like me coz you forgot to back up your iDisk, then you can calm down a bit. Yes, MobileMe ended on June 30, 2012, and iDisk syncing is no longer available. But perhaps your files are backed up by osx.
Check and see if you have a folder called Previous local iDisks folder on your Desktop. If you see it, then you are in luck. Double-clicking on the image file will give you back all your files.
Now is the time to do your backup. ;)