[Qmulus]

The basic rule for the oil pressure light is that if it comes on, you MUST turn off the ignition immediately. Continuing to run the engine with no oil pressure means certain damage to the engine. I have a bunch of cases where people damage the oil pan, lose the oil and continue to drive with the oil light glowing. It invariability ends in engine replacement. Had they turned it off as soon as the light came on, it may have lived. I hope for your sake that you just have a lifter that isn't pumping up, but I'm not optimistic.

My guess is that the noise you are hearing now is a bit of rod knock. I think that it is time to pull the pan to assess the damage.

If you do keep driving it, and it is a rod bearing, chances are very good that it will fail catastrophically. I saw a Boxster that had been driven with rod knock, ending with a beautiful R&R rod breaking and destroying what had been a very expensive engine. The sad part is the owner heard the noise and decided to press on. That was a very expensive decision.