Last night I was working on installing vsftpd on my Ubuntu 12.10 server. I shutdown last night and when I booted up this morning I seemed to have lost the abilities to sudo anything. It just says, "** is not in the sudoers file. This incident will be reported." Now I wasn't messing with any sudo files, just /etc/vsftpd.confg and /etc/shells. So how did I seemingly lose sudo ability? I'm rather new to Linux in general, but I'm picking it up quick.
if your not in the sudoers file you could use the rescue mode and put yourself back in.
IT should be as simple as going into rescue mode and using the root account to add your account to the sudoers file
Here is that info How can I add a new user as sudoer using the command line?