Any time the furnace breaks down, you may be stressed. This is particularly true if it's during the middle of winter. The best thing you can do in this situation is to hire a heating repair contractor. They can address all sorts of issues today.
If you're not on top of your filter changing routine, the ducts of your HVAC system can get so dirty that they clog. Then, your furnace has to work a lot harder and could potentially overheat.