Oil pressure dropping to 0

My oil pressure drops to 0 after about ten
miles. Changes the sensor and screen under
sensor. No change. Changed oil pump, O ring,
cleaned oil pan and pick up. Was at 55 psi
cold and went down to 40 a it warmed up.
Then slowly dropped to 0 and the light came
on about 5 moles from home. Shit it off and let
it sit for about 10 minutes. Fired it up and
drove home. Dropped to about 30 while
driving home but didn’t drop all the way
down. If I drive it for about 10 miles it drops to
0.