Baby won't poop

Kari
So I called the doctor and they said it was normal.  But I don't see how a baby not pooping for over 24 hours is normal. 
His last pool was at 8pm on Tuesday. It is now 9:40am on Thursday... And still no poop. 
I dont know what's wrong with him or what to do. 
I dont think he's constipated?? He isn't fussy or anything he is all smiles and happy and his tummy isn't hard. What should I do? Is this normal??