[travelin texans]

Are talking Celsius or Fahrenheit? Your t stat may set to F or C causing the confusion.
Also that rv was never designed to be used in that cold of environment, not much insulation in the walls, roof or underneath, you'll most likely need some heat sources other than the onboard furnace to ever get it almost comfortable in those temps.
The FW tank is probably under the bed so a heat source there will be required to thaw that as well.