Parallels on Mac - can no longer sudo within Ubuntu

I have been using Parallels on my Mac to run Ubuntu for a couple of weeks and it's been fine. Today I tried to install a package and received the following error: > {user} is not in the sudoers file. This incident will be reported. when I vim /etc/sudoers:

 #
 # This file MUST be edited with the 'visudo' command as root.
 #
 # Please consider adding local content in /etc/sudoers.d/ instead of
 # directly modifying this file.
 #
 # See the man page for details on how to write a sudoers file.
 # Defaults        env_reset Defaults        mail_badpass Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 
 # Host alias specification
 
 # User alias specification
 
 # Cmnd alias specification
 
 # User privilege specification root    ALL=(ALL:ALL) ALL
 
 # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL
 
 # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL
 
 # See sudoers(5) for more information on "#include" directives:
 
 #includedir /etc/sudoers.d

This was working fine yesterday and I have made no changes to the sudoers file. I also can't access the boot menu to start in recovery mode. Does anyone have any ideas how to solve this?