Following is the output of df -h on my system. 
Filesystem      Size  Used Avail Use% Mounted on
udev             63G     0   63G   0% /dev
tmpfs            13G   18M   13G   1% /run
/dev/sdc4       822G  801G     0 100% /
tmpfs            63G   64M   63G   1% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs            63G     0   63G   0% /sys/fs/cgroup
/dev/nvme1n1p2   96M   75M   22M  79% /boot/efi
cgmfs           100K     0  100K   0% /run/cgmanager/fs
tmpfs            13G   88K   13G   1% /run/user/1000
Using du -xsch /home, I get the following:
60G /home
60G total
Using free -m, I get the following:
total        used        free      shared  buff/cache   available
Mem:         128831        8648       16405         147      103777      118367
Swap:        130986          18      130968
I only recently moved to using Linux, so I am not aware yet of how the disk partitioning is used. It also seems weird that my system had more than 500 GB yesterday, but just today it's started to show Free space: 0 bytes at the bottom of every folder I open. This space error is causing things to hangup.
EDIT: I have deleted some files in excess of 40 GB, but it still shows Free space: 0 bytes at the bottom of each folder, and does not allow me to copy any files. I am stunned that it was showing ~550 GB yesterday as the free space and suddenly all of it vanished, although there was nothing I did to occupy that space.
 
     
    