The exact same thing happened with DS about a week ago. I chalked it up to a maturing digestive system. He's only had breastmilk as well, so I know it's not a change in diet. He's also not pooping as often or spitting up as much too, so that's what lead me to my conclusion.
Me: unexplained infertility - annovulatory
DH: testicular cancer survivor!!
TTC since June 2009
BFP May 11, 2012
EDD January 24, 2013
June 1, 2012 - first u/s, heartbeat 124 BPM!!
June 22, 2012 - heard the heartbeat 9w1d 181 BPM!!
24 hours of labor, 4 1/2 hours of pushing, and IT'S A BOY!
Welcome to the world my miracle, we prayed and prayed for you, and we can't believe you're here!
DS's poop has changed and looks exactly like what you are describing. He also used to poop all the time and now he is only going every one to two days. Is your LO teething? I've heard that when babies start teething sometimes their poop changes. Not sure why but this fits with my LO. No teeth yet but all the other signs of teething are there!
Re: creamy poop
Here are a few visual guides.
https://www.babycenter.com/baby-poop-photos
https://similac.com/feeding-nutrition/diaper-decoder