Hi, I have a 2009 Camry SE and got my oil changed at Jiffy Lube right after Christmas 2010. They told me I'm good to go for 5000 miles (I requested synthetic, which turned out not to be class 4 full synthetic, but class 3 refined instead - ugh), but the oil change reminder light comes on after 4 months, which I ignored.

Yesterday, I changed the oil & filter myself, and was shocked the used oil was nearly black except when spread very thin. I only drove ~2000 miles since the oil change. I live around the San Francisco bay area, and almost all my trips are local < 4 mile, stop and go. Is the oil supposed to wear out this fast?