You've probably been hit with the notorious Windows 10 Anniversary Update. This update is known to sometimes wipe out Linux/Ubuntu partitions (why? only Microsoft knows). If you can post a current-window-only screenshot of gparted, I can confirm this case.
Recovery, short of reinstalling Ubuntu, can be difficult, but it may be possible through the use of the testdisk application. Search AskUbuntu for "testdisk" to read what others experience is.
To run testdisk, you need to boot to a Ubuntu Live DVD and install testdisk. Once booted, you open a terminal window and type the following three commands, one at a time. Suggest copy and paste.
sudo apt-get update
sudo apt-get install testdisk
sudo testdisk
For a step-by-step intro to recovery using testdisk, visit http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step.