I've noticed that when the car is warmed up and sitting at idle around 800ish the oil pressure (from the pro-sport gauge

) says about 15psi........
One i get on her it stays right around 60-70 psi. Cruising it sits around 30-40. The idle kinda scares the [shizzle] out of me, i realize the engine is relatively moving pretty slow at that point but 15psi just seems to damn low. Is that right though?