Yeast don't die at low temps, they just basically hybernate.
You are bottle conditioning at room temp, correct? What is the ambiant temp where you are bottle carbing/conditioning? If you are below 72F, your carb time might take longer. If you are below 60F or so, it is too cold to carb at all.
After a cold crash, yeast tend to be sluggish when you first bring them back up to room temp for bottling, but as long as there is sugar, they will reanimate and eat that sugar.
Worse comes to worse, you may need to open all the bottles, sprinkle a tiny bit of US-04 into each bottle, and recap.