Moving out the way

Memes • Hi. I am 26 years old and a mother of a 7yr old son. My fiance and I are expecting our second child in Jan. 2018.
Has anyone who already has a child heard the saying "their getting out of the way for the new baby". My 4 year old has always been a bed wetter, literally every night. I am suspecting I am preggo this month. I am experiencing all the symptoms. A while ago my son just amazingly stopped wetting the bed. Haven't had an incident in 2 weeks. Maybe he's "getting out the way". Anyone else experience this pregnant with a younger child already?