Gas Bill Craziness

I know I can't complain much about our gas bills in general since they are way way less than our friends' bills on the East Coast but... I was shocked when our bill tripled, yes tripled, since last month! The only thing I hope we have going for us is that our last read was an actual read and this read is an estimate. I so hope they are over estimating!! We don't keep our house extremely warm either, about 72. Joe would like it much warmer, but I'm too cheap. I'm knocking it down to 70 and telling Joe to wear a sweater. I try to remember to turn it down before I leave for the day, but I'm constantly forgetting. Perhaps I'll remember now.