If you forgot to backup your stuff, stop using this drive and call up drivesavers.com to see what they can get back.
Continued use, even booting up can overwrite what you forget to backup.
I wanted to install Ubuntu alongside a Bootcamp Mac, so I shrunk my Windows partition. Once I did that, I converted it to a simple volume to see what that would do, but it ended up converting the whole drive. When I tried to fix it, the computer restarted due to an update. Now when I load up my Mac, I only see the Windows drive, but it doesn't load all the way. IS THERE ANYTHING TO GET MY PARTITIONS AND DATA BACK?