If the engine will start but the car won't move, check the gas gauge. Conserve gasoline by running the engine and heater only 10 minutes or so out of each half hour or hour. If the area is snowy, check that the tailpipe is clear so exhaust won't be trapped under the car. Police report that exhaust poisoning is a major cause of death for motorists whose cars get stranded in deep snow. No matter how thirsty you get, never eat snow when in danger from cold.
Snow requires so much body heat to melt that rapid hypothermia can result.
Instead, melt it in a hubcap over your candle. Times like these make a cellular phone or mobile ham radio look mighty good. It provides by far the driest, most windproof, most comfortable shelter you could possibly devise in the wilds. It's also highly visible. Poor judgment leading to gross stupidity is a classic effect of oncoming hypothermia.