Your newborn is likely to have his or her days and nights mixed up for anywhere between 1 to 12 weeks. This is because during pregnancy your daytime activities rocked your baby to sleep and at night when you were relaxing your baby was more active. Also, it’s not until about 12-15 weeks that babies start producing enough of their sleep/awake hormones so they can have the timings mixed up.
But with age, it gets better and the child gets used to following a day and night ritual.