Motor oil in the coolant is typically caused by the Timing Chain wearing a hole thru the TC cover, allowing engine oil into the water jacket.
Does your motor oil have coolant in it ?
Another possibility is a blown head gasket.
Usually you'll see other signs of that too, like sweet smelling white exhaust from burning coolant.
I'd stop driving it until you get things sorted out.
Coolant in the oil isn't good for engine bearings, for starters.