So now, $1680 later, the laptop has had its data recovered--something like 497,000 files--and I have a new external hard drive holding all that data, and laptoppie-poo is on its way to Apple for a new hard drive.
An expensive lesson, for sure. But with all the minor and major horrors going on all around us, I feel lucky that that's all it was. Odd reaction, maybe. But I'm not freaking out.
My back up plan for my new hard drive is in place, though.