I would not drive this car before a good investigation. Suspicions are a oil pump sprocket with teeth problems or the oil pump driving chain tensioner. Or some combination. At least inspection is not hard to do with the small portion of the oil pan being removable. Also may be in the oil pump itself is something has broken up perhaps. That is not too likely though. Of course it may be something simpler Just stop using the car before finding out.. The oil pressure upper limit valve on the oil pump might just be randomly hanging up.. This too is inspectable.

As the last poster said basically you cannot ignore your symptom. You may also already have been lucky all oil pressure was not lost. Of course you are sure the oil level in the engine is showing on the dipstick?

All these suggestions are based on having the mechanical oil gauge system. If you have the electric one the problem is probably in the pressure reading circuit. Like a shaky pressure sensor perhaps. It is old enough to easily develop internal contact problems.Nothing lasts forever.