The first two weeks of your newborn's life is a separate stage. During this time, your baby will basically only eat and sleep. This grace period is precious: allowing you to recover from pregnancy and birth, get breastfeeding established, and get settled in with your newborn. Once your baby hits their first growth spurt (around 2 weeks), everything changes.
Most new parents don't know about this. They think their baby is just "easy" and will continue the same way. Still riding an adrenaline high, they may waste their energy on day to day chores, entertaining guests, etc. When, all of a sudden, their baby gets fussy and doesn't want to be put down for 24-48 hours, they panic.
After the growth spurt, your baby "wakes up." Babies who seemed oblivious to their environment before may now have an opinion about everything. Reflux, food sensitivities and allergies often present themselves in the third week. The parents who missed their window to prepare are now overwhelmed and stunned.
If you recognize the first two weeks as a precious window, you can conserve your energy, maximize your sleep, and be ready when your baby's behavior dramatically changes. Postpartum largely depends on pacing--the slower you go, the easier it will be.
**This applies to full term babies. Preterm, postdates and late preterm babies often stay closer to their gestational ages. (i.e. my third baby, at 41.5 weeks, was literally born in her growth spurt.)
Postpartum Doula, Breastfeeding Counselor, Mother of Three.