I weary of the mysticism attributed to various parturitional phenomena. Why does it have to be magic*? These things just make sense. Call it hormones if it makes you happy, I guess; I'd rather imagine that I still have some capacity for a valid analytical response to stimuli.
1. Nesting: a completely rational reaction to knowing that one's house will be mostly neglected for something like a year after the baby is born. No, this shape I'm in is not the most practical for some of the random projects I find myself undertaking in trimesters 2 and 3. But if I don't do them now, they absolutely won't get done later.
2. Post-delivery "high": again, a totally reasonable and predictable reaction to having a healthy baby, having L&D over with, and not being gordo pregnant any more. Freakin duh. (Not to mention that if the alleged nursing "high" were more widely or meaningfully experienced, more people would nurse for longer than three weeks. Oxytocin, the least effective miracle hormone in the universe.)
3. Pregnant/postpartum brain: The BSG "33" sleep schedule alone accounts for this; why even mention the other variables?
*I know, it's not magical, it's brain chemistry. Magical brain chemistry!