I agree with the drain, refill, pray and crank her over advice. Mostly whatever's done is done. It's possible that when you overfilled the oil some of it blew by and into the cylinder and what you experienced was 'runaway diesel' and this is why it wouldn't shut off despite turning off the ignition. You'll know a lot after the first crank. If she fires up and runs true you dodged a bullet. If she won't crank or fires up and knocks stop, do not pass go and take her straight to the doctors office!
Good luck! We all done dumb things, many of us havedone the same ones more than twice. All you can do is dust yourself off and keep rolling on.