You didn't drive your car to work, did you? If you did...oh noes!
I'd have guessed your pop was ET, and that you don't have coolant. ETs pop...and then the plastic being so brittle, crack in such a way that it's hard to see. Also, when you shut down after an ET crack, they often seal themselves...the pressure from the system is quickly relieved with a cracked anything...and the coolant could easily have been blown back off the underskirt.
You need to find the leak, the reason why you have a leak (which might be more than that the ET popped, for instance). A closed therm is definitely a reason why the system would overheat.
$300 buys you a whole system (another $150 if you need a radiator...which you might at around 150K or above typically).
I'll save you the long cooling lecture as you can find it all over the place.
VCG is straightforward...but should be fixed. Figure 4 hours the first time (another 4 hours learning how to do it)...under 2 after that.
Upcoming NYC dates: Jan 8 and 27. See Facebook for other shows and PM me if you can make one...love to see you there!
Mangofy your E46!