Baby constipated?¿

Trista • 16 years old and due date on October 28th 2015 💙 having a little boy named Forrest Nathaniel Keister 👶🏻
My baby who is 11 days old has not pooped at all today! I'm a first time mom & im a little worried because he has popped everyday until today! He's still peeing like mad crazy though lol! I don't think he's in pain and he's still eating regularly and he is half breast and half formula fed (due to not wanting to latch on my breast) should I be worried and is there anything I can do to make him poop!