Droopy

I have a 2009 Camry SE and i change my oil every 5 months or 3k miles. I do alot of city driving and by the time i'm around the 3k mile mark my oil has a dark tint to it. I curretly run 5w20 synpower by valvoline and a pureone premium oil filter. If I was driving more with more highway miles i would go maybe 4k miles at the most.