Disk space lost after quitting disk partition
You probably tried to manipulate a CoreStorage volume with Disk Utility. Core Storage volumes are built after enabling File Vault 2, creating a Fusion Drive or often after updating to Yosemite.

If you don't have a second internal hard disk attached, disk0 is usually mounted to /. In your case disk1 is mounted to / which is a typical hint for Core Storage Volume Group - in case of an internal Fusion Drive disk2 is mounted to / and disk0 and disk1 usually don't appear entering df -h.

Open Terminal and enter diskutil cs list to get all CoreStorage objects in a tree-like view.

Use this comprehensive list of documented and undocumented commands to manipulate your CoreStorage Volume Group.