Could be the sensor going bad. How low on oil were you and for how long do you think? Any weird knocking noises going on? I just hit 186,400 on the way back from an Event out in Big Bend and I think still getting 50-60 psi at highway speeds and I think I see 20-30ish at idle around town. I'll have to pay more attention to it next time I'm out and about in the car. I usually just glance and make sure it's pointing in the right direction when I'm driving lol.
Let me bust out my service manual and see what it has for the oil pressure spec.
Edit- Found it.
Oil Pressure
With engine at operating temperature, oil pressure should be 28-43psi at 1000 rpm, and 43-57psi at 3000 rpm.