Low Oil Pressure

My 2003 Chevy Suburban 1500 5.3 4x4 is getting a “Low
oil pressure” alarm. I replaced the oil pressure sensor, but
got the same alarm.  After some research I saw the
discussions about replacing the o-ring on the oil uptake
tube.  I did that, however the problem persisted.  I noticed
a lot of oil around the oil pressure sensor.  Realizing that it
was leaking I replaced it with another new one.  It now
had pressure and was reading 40 and would go up
appropriately under acceleration. After 4 days, the alarm
came back and it was spitting oil from the sending unit
again. I pulled the oil pressure sensor and sucked on it
and it wasn’t sealed; meaning I was able to draw air
through the sensor. I swapped it again (3rd time). Before
installed I again sucked on the new one and it was sealed.
I wasn’t able to draw air, so I installed it and had perfect
pressure for 2 days and then the same issue presented
itself again.  I’m leaning towards a failing pump. If anyone
had any suggestions, please let me know. Thank you!