Oil in diesels will look contaminated in no time after the change. Not unusual.
Most will suggest oil/filter changes every 3000 miles (or less), and then there is enough info for a PhD dissertation on oil selection.
I'm using 1-gallon jugs of Shell Rotella (because it can be bought cheap by the case at Sam's Club) and plan on changing the oil/filter every other month, irregardless of mileage, which will be far less them 3000 miles.
Not to start something here, but in most of my monitoring of posts on this subject matter the popular notion is diesels need to be run steady and hard for extended periods to keep things cleared out and the car happy. We use ours almost exclusively for hauling the kids to their grandparents an hour away via the interstate or for trips that involve several hours of driving.
If there is puttering around town on short trips, usually there is a trip down the interstate soon afterwards that helps clear things out.