Swap sensors and/or test with a real oil pressure gauge threaded into the sensor port.
You could also check your pressure relief valve under the case to make sure it is clean, not scored, or gunked up and sticking.
Not uncommon for the light to start suddenly flickering especially at idle even when it didn't the day before. In my case, when that occurred on my original 1.7L it did mean it was time for bearings (and upgraded displacement!).
Think about the possibility. The day before, you were right on the ragged edge of having it turn on, but, it didn't. Then you went out and drove the vehicle, and wore just a bit more off the bearings when things were hot, loose, and the oil pressure was lacking a bit.
Next day, you fire it up and light flickers at idle.
I've been there. This is exactly how it was for me.
I'm hoping in your case, that maybe you do find good pressure at the port and a bad sensor.
If pressure is indeed low, rebuild with new bearings before catastrophic failure occurs. Light is there for a reason.