Does the engine spin freely with the starter and just won't fire up and run, or does it crank slowly or not at all? It's possible the distributor slipped upward in the clamp a little and disengaged the oil pump drive. If that's the case, you could have some major bearing and/or crankshaft damage. If it spins freely, I'd suggest removing the distributor and running the oil pump with a straight screwdriver bit in a drill motor to see if it has normal oil pressure before trying to start the engine again. If it's hard to crank, or won't turn at all, you'll need to drop the oil pan and inspect some bearings.
Jerry
