Sounds very familiar.
Just as you think you are over the worst and sailing along fairly comfortably; Wham!! Something happens that immediately makes you think of smoking to make a situation better (likely you used cigs in the past to calm you when you were with your son and things were ... well, let's just say busy?)
This is completely normal so don't worry too much about it. Put your early quit strategies into play and beat back these recent, unexpected strong urges. They will eventually stop happening once your addiction understands; YOU WON & it lost the war against addiction!