[kugelfischer]

First thing to do it is to confirm your actual oil pressure using a mechanical guage, not the dash guage. As you know, the dash guage is notoriously inaccurate. Additionally, it's possible that your pressure sender has gone bad.
Next would be to address the knocking sounds. There can be MANY possible sources, but to be honest, I wouldn't Plano driving the car much until you get this sorted out. Many of the sources are potentially damaging to the engine.

Well, maybe not in that order but I'd do both before running the car too much at this point.