If you are unsure when the rear shoes were done last, it's probably a good idea to check them. Like Ian said, if you didn't notice the parking break on, the rear brakes likely need an adjustment.
That's terrible.
You are not alone.
My Dad had a similar issue a couple years ago. On the way home from a road trip he was pulling into a gas station when the engine made a noise and abruptly shut off. He did not know what it was until he pulled the head. Part of the aluminum head broke and allowed water to fill the cylinder. At this point, he still did not know what caused it. A close inspection of what was beleived to be a peice of the head was actually a squashed nut. He doesn't remember losing one but he must have accidently dropped one down the carb.
The funny thing is that he had just put a ton of miles on the car without messing with the engine. He even did some slalom racing while at a Corvette convention 900 miles from home. It must have been sitting in the intake for some time then eventually made it in the cylinder. We thought that it was very lucky that it broke the head only 20 minutes from home.