To fix this I had to pick ADVANCED in the GRUB menu on startup of the virtual and pick a previous working kernel version to boot with. This booted me with an older version of the kernel but it was functioning.
I then started a TERMINAL and typed the following two commands:
sudo update-initramfs -u -k VERSION*
sudo update-grub
Replace VERSION* with the name of the version giving you the panic error, in my case it was 4.15.0-47-generic. So my command was: sudo update-initramfs -u -k 4.15.0-47-generic
That's it, you should be able to restart the system and it will boot normally. If it doesn't here's a link to an article that may provide more help on this topic. LINK HERE And here is a link to the GRUB2 manual. GRUB2 Manual
NOTE: the 2nd picture is of an older version of GRUB and is only there to give you an idea of what you'll see. It is not a capture of my screen (I forgot) so this is just a googled image used as an example to aid you.
