When I did, it was prayer, telling people I had it, and making some time for myself to go to the gym by putting kids in nursery 1/2 day.
Also, I wanted people to sympathise, NOT tell me it probably wasn't PND, or that I just felt down because DS didn't sleep etc.
I loved it when people took charge and said "right, I am coming to your house today with your dinner, and I will take your DD away with me for an hour", rather than making me decide if I wanted help or not!
But my friend has PND atm, and she seems really bad - doesn't even want to leave the house I wondered what helped others, as she is very different personality from me, so what helped me may not help her.