Water pump on its way out?

The car: 2007 BMW 328xi coupe 6-speed MT with 85,000 miles. The problem: I am driving north on the 101 near Santa Rosa Ca, and I get the yellow overheat light that turns red almost immediately. The car goes into limp mode and I pull over as fast as I can. I lift the hood and there is what seems to be oil all over my engine bay and oil on the ground coming from my coolant reservoir. It's not frothy, nor does it look like water is mixed in, it looks/feels like straight up synthetic oil. I get back in the car and start up the engine (I know, not a good idea) and proceed to drive back home (200 miles) checking the car's vitals the entire way (note the overheat light did not come back on at any time). I make it all the way home without any incident and the engine seems to be running great with an oil temp of around 230 F the entire way. When I get home, I open the hood and it's like the overheat didn't even happen, i.e. no oil residue anywhere and no more leaking oily substance. My coolant reservoir is now empty, but is covered (inside the reservoir) in a light golden brown oily substance. Is this a sign of the water pump going out? And what's up with the oily coolant? Is our BMW antifreeze the same color and viscosity of engine oil?