Never mind, I'm an idiot. I forgot that I forgot to take the car for a test drive, so the engine wasn't fully up to temp (I figured 25% on the temp gauge was good enough). When I looked at the coolant temperature, I realized that it wasn't hot enough to get the heater going. Took it for a drive, worked beautifully, problem solved, now I know to think things through more carefully before I freak out. I also know a lot more about how the HVAC system in this car works.