Have you pulled the plugs as first suggested to see if they show evidence of oil burning across all cylinders? If they are, that probably points to a turbo problem as others are suggesting.

Running that low on oil twice has probably caused some major damage to the engine internals. I'm not sure what else we can help you with. It should be towed to a mechanic you can trust imo.

 

If it is the turbo seal oil may be leaking only on the inlet side not going out the exhaust. Which case you would be filling the hot side pipe and intercooler with oil. That much oil is going somewhere.