Sounds like the old favourite...injector seals! Easy and cheap to do and certainly cheaper than replacing the turbo.
If its no better after the seals have been done get your injectors tested.
But diesel in the oil is usually seals, or worse case a cracked head, to check for that, remove the cam cover, turn on ignition and using a torch look very closely around the injector pockets, if you see any "flows" it means the heads cracked or a seal has gone, when you remove the injectors check the injector pockets for cracks.
Dont keep driving it! Worse case is it will run away, running on its own oil/diesel.
Mark