I found out the gas company had shut off my meter because they had a broken gas line in the neighborhood and had to shut off the gas. Since there was nobody home during the day, they couldn't get into the house to light any pilot lights, so they shut the meter off as a precaution. Didn't even leave me a note. I didn't notice until the next day in the middle of a shower when everything went cold!
PS try shutting off the power to the furnace for 1 minute and turning it back on. It may have to be "reset" in that manner.