Is it possible to have quit smoking because of a cold?

Yes: many people, even heavy smokers, find that they cannot smoke when they have a URI, because it so increases their coughing or congestion. Some people use this as a "head start" in continuing smoking cessation. If this is you, I strongly recommend you do the single best thing you can do for your health and quit smoking. Use a formal cessation program, possibly with medications as well.