What don't you understand about it already being too late? Telling people to change to a different weight is not going to help and only confuse them.
Under normal circumstances, when the oil gets old and hot, it will lose the ability to maintain pressure. I have verified this many times. Yes oil pressure will fall down to about 30 psi. Once the oil is changed with normal weight(5W-30) or (10W-30), oil pressure will return back to roughly 50 psi cold, and about 40 hot. Once about 3 months goes by, you will notice a high cold pressure, then a low warm pressure. This is completely normal. In your case, the filter is clogging up with metal shavings STARVING the engine of oil.
1997 Pontiac Bonneville SEi-SCRAPYARD
2000 Chevrolet Blazer LT 4X4 4.3L
2002 Chevrolet *-10 LS Ext Cab 4X4 5.7 V8