Ah, so you had Nemo on your device.
That explains the loss of space; When you install nemo it will split a part of your mmcblk0p1 to create a new partition number 4 where the Nemo filesyste is created.

With command "/sbin/sfdisk -l" as devel-su you can see the full pertition details...

The way that your setup looks is something like this:

/dev/mmcblk0p1 4G (MyDocs)
/dev/mmcblk0p4 4G (Nemo)
/dev/mmcblk0p2 4G (root)
/dev/mmcblk0p3 2G (home)

Now, what you can do, is back up your existing data from MyDocs (if you have something you want to keep, that is), and repartition the mmcblk so that you remove the mmcblk0p4 partition and grow back the mmcblk0p1 to the full size.
Then reformat the new mmcblk0p1 partition and restore backup.