I had that happen at a job once. I get terrible social anxiety. What might help you is to type out a nice resignation letter (instead of verbally saying that you're quitting). Say that you will work those double hours, since you made a commitment but, also, say you will be leaving after that 1 month is plenty of notice (you're only required to give two weeks). Hand it to your boss (preferably at the end of your shift in case there's any kind of confrontation). Good luck!

practice what needs to be said.. like.... are you talking to me, are you talking me punk... no.. well, in that case, I quit!

take a shift, hate your life for a few hours, make a buck :)

OP must be my doppelganger, because this is literally my life. Same job and debilitating anxiety. I feel your pain!

How does one accidental do that?

Just tell them it was a mistake and that you need to quit, unless you really are prepared to work that many hours. :)

a mcjob? I wouldn't give notice. if you want to quit that job just don't show up. easy as that.

It's a bit cowardly but you could just not show up or answer their calls.

It's OK. You're not the first person to quit, and you won't be the last. You aren't going to break your boss's heart or insult her/him personally. This is simply business, and they'll understand.

Well write a script...and read it or write a note...