This is no time for the heater to be tempermental!

Sitting here at the keyboard typing away I notice that the radiator is cold which is odd because its been on all day. The temperatures have been in the 40's all day and right now its 38 degrees outside! So why is the radiator cold? So I went to check the thermostate to see what the house temperature is and its like 62 which means the heater should be on. So I flip the switch that designates the "cold/vs hot temperature" and slowly the radiators start to warm up. They are hot now. Besides my little panic attack I'm sure that if I had left it at its setting the radiators would have started. I sure hope there's nothing wrong with the furnace!