check engine oil pressure light

I own a 2001 chev silverado ex cab 4x4 with 125,000 kms. The other day I started the truck with com. start before work. When I got in the truck to go to work the check engine oil pressure message was on with the gauge reading just above 0. Figuring it was just the crazy sensors acting up I shut it off and checked the oil... oil level was right on with about 1500k on the oil and filter (syn 5w30). I then drove to work about 1.5 miles away and about halfway there the engine died. Tried to start the engine and it seemed a little tight. Although I did not start the engine I got it towed into the local mechanic to take a look. He got in and tryed to start it. It started perfectly with a slight ticking from the motor. The oil pressure came back to normal and the ticking from the motor completeley stopped and has never acted up since. The temp outside was about -20C that morning but was plugged in. Has anyone ever experienced this. could it be condensation in the oil or filter? Any tips or suggestions will be greatly appreciated. Thanks in advance.