EDIT: Resolved. I stopped the pump, removed the pump basket and cleaned it out. It seemed relatively clean from the outside, but there were lots of little stones and bits of PVC sticking in the basket. Pressure is back to 15 psi again!
I got my pump working this morning...yay. One concern is that I see the sand filter already went from a "clean" pressure of 15psi to 19psi in the first couple of hours of operation. Is this normal? I skimmed the pool with a fine leaf rake as well as I could before turning on the pump. I also lifted out the skimmer baskets to ensure that they weren't causing the pressure increase.
Should I attempt to backflush and rinse?