Since the temp dropped below zero for the first time last night, my furnace is having problems and is not working as it should.

I woke up this morning and the temp was 57 when it should have been 72.

I reset the programmable thermostat, reprogramed it, went down to the furnace and pushed the red reset button and it fired right up. It cycled off, and about 45 minutes later, it cycled back on as it should. Then, it wouldn't fire up again.

This time, I had to push the red reset on the furnace about 7 times before it finally fired up again.

It has done this about three times today, each time, it takes several tries of the reset button to get it to fire up.

Any idea what my problem might be?

I guess you have a oil furnace? You did not state this important item.

You probably haver a oil delivery problem. Air in the oil lines or a air leak in the oil lines/filter assembly are the usual cause. A weak transformer,oil pump,cad cell,and other parts can also cause this type of problem.

Stop pushing the reset button and call a professional to fix it. Oil heat is not something to play with and if you do not know what you are doing you can make matters worse.

Since the temp dropped below zero for the first time last night, my furnace is having problems and is not working as it should.

I woke up this morning and the temp was 57 when it should have been 72.

I reset the programable thermostat, reprogramed it, went down to the furnace and pushed the red reset button and it fired right up. It cycled off, and about 45 mins later, it cycled back on as it should. Then, it wouldn't fire up again.

This time, I had to push the red reset on the furnace about 7 times before it finally fired up again.

It has done this about three times today, each time, it takes several tries of the reset button to get it to fire up.

Any idea what my problem might be?
It is a natural gas forced air unit, very old, but you can't beat the heat this thing puts out when its working right. I did some research yesterday and here is what I believe the problem is. First, it has not failed to fire up since I asked the question so for now, I'm just going to leave it alone. I think I have a weak thermo coupler? Since the reset works so randomly, the thermo coupler is what I plan to replace first if the problem presents itself again. If the thermo coupler doesn't solve the issue, I think I'll go with a new thermostat. If that fails, I'll be back here looking for more help. Thanks for your response!