09 silverado 1500 5.3 ticking help

[Sub_zero4829]

I do not know much about vehicles and unfortunately my brother and dad are out of state right now, and their usually the ones that help me fix my vehicle. This is my first truck and i bought it already with a very small/barley noticeable lifter tick with the intentions on addressing it eventually. Well i might have waited too long but im not sure. Like i said i bought it with a lifter tick but the other day i pulled into the parking lot and noticed i had low oil pressure, so i just ran inside quick. Left the truck running and i came outside, from the gas station door i could hear the ticking coming from my truck. What was a small tick is now a very loud tick/small knock. Open my truck door and it was dinging nonstop, telling me to shut down, and had little to zero oil pressure. Got it home and today it has pressure but fluctuates alot. I replaces the oil pressure sensor a few months ago, the gauge stopped working. So thats already good, ive been researching into it and i found it could be a little screen under the sensor thats clauged, pickup tube clauged, or the oring on the pickup tube are the most common problems ive found so far... im just curious if anyone could point me in the right direction or has any suggestions. And i havent brought it in yet or anything to get a oil pressure test done on it, so should i start there?... sorry for the long paragraph lol any help at all would be very much appreciated! Thank you