Loosing that much oil if that quickly I would look to see for obvious leaks.
Is there an emulsion in the oil filler cap like mayonnaise or in the water header tank?
I assume it isn't burning oil as you would have seen black / grey smoke in clouds from the exhaust.
Smoke in the foot well might be oil burning off on the exhaust as it leaks.
As Image says I'd drain it to check just how much remains.
