Ok after fitting my new oil pump gears im having problems again.

i have a rebuilt C20LET, new pistons re-bore vandavall shells, bearings etc etc .

the engine is completly std. im just running it in,only done 220 miles

did 90 miles today, ran fine.
went home had dinner, got in the car a few hours latter and i have no oil preesue, the light wouldn't go out.

is my pressure relief valve stuck again?