Are you checking the dipstick or just going by the oil light?
You should be using BMW 5w30 or Mobil 1 0w40...or a few others but those are my recommendations. Make sure you check the dipstick. In case you haven't heard...our oil level sensors are garbage. Mine comes on frequently, even the day I change my oil. After you run your car, open your oil cap...does it smell like burnt oil? Does your exhaust smoke?