I managed to borde my sudo... I have a backup of the system that I can try restore. However, since sudo is broken I can't overwrite files that are protected.
Guidelines I tired to follow when making and restoring the backup: https://help.ubuntu.com/community/BackupYourSystem/TAR
Basically I want to run
sudo tar -xvpzf /path/to/backup.tar.gz -C / --numeric-owner
sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set