Was the heat hot? (Not that I think you could tell in this weather.) If so, it's probably not the wp (at least not classic Duratec impeller meltdown). Good idea to replace the stat, pump, belt (might as well at that point), and flush it. Don't forget to replace the rad cap.
Sounds to me that you lost coolant somehow. See any drips under the car in the driveway? Maybe the wp failed in the classic failure - blown seal allowing coolant to weep out of the pump. My wife's 88 Olds did that a few months ago. Not a drop of coolant left in the overflow, heat was still hot, and temp idiot light was coming on (no gauge). When I pulled her pump off, I could see evidence of coolant coming out of the weep hole which was hidden when the pulley was still installed. I did the whole cooling system tune up (including new hoses), and she's been fine since.
Unless you pegged the temp gauge for a significant time, you *should* be fine. Our cars actually have a Cylinder Head Temp sensor, which is supposed to cut spark to allow the fuel charge to cool the cylinder in an overheat condition. Doesn't seem to have helped people here when their pump died.
