My baby hasn't slept through the night yet, but she generally is 'sleepy through the night'. But last night she was wide awake at 4am, eager to play. Then she had a huge poo. What is going on?!? How can I prevent this from happening tonight?

Might be your baby was not tired that day thats or else she had wet nappy or may be she is hungry above may be the reason for your baby not sleepy through the night you can avoid this situation by make sure she exercised properly in the day , before sleep she had a stomach full and you can always start with the bed routine for your child