Kernel Panic Issue - not syncing VFS, unable to mount root fs

I suddenly got a notification of my CPU usage being high, and when I check my website - it was down.

And, then tried to log in to FTP to deactivate WordPress plugins to see if it’s an issue with WordPress (but couldn’t access FTP/SSH as well)

Then I went to the dashboard and tried to access the console of Digital Ocean, and it displayed the following error in the image below:

http://prntscr.com/o1z7au

The last DO support response was to go to the recovery mode then:

-check filesystem -mount disk image (or filesystem) (is it the same thing?) (Refer to this: https://www.digitalocean.com/docs/droplets/resources/recovery-iso/)

Then change the recovery mode to HDD and then power back on the droplet.

Maybe I misunderstood the official support response? Or did I miss something else?

I also tried restoring the droplet backup - that didn’t work either. Do I have to fix the issue before trying to restore the backup?

I’m kinda in a panic mode - so please help me with a detailed response. I don’t know how the hell did this problem occur in the first place.