Identify the Symptoms
At some point, you're going to need to distinguish symptoms of the new-mom culture shock and its accompanying baby blues from a bona fide mood disorder. You can find a list of the standard symptoms for postpartum depression by clicking here, but better than that, I think, is the description actress Brooke Shields gives in her memoir, Down Came the Rain:
"At first I thought what I was feeling was just exhaustion, but with it came an overriding sense of panic that I had never felt before. Rowan kept crying, and I began to dread the moment when Chris would bring her back to me. I started to experience a sick sensation in my stomach; it was as if a vise were tightening around my chest. Instead of the nervous anxiety that often accompanies panic, a feeling of devastation overcame me. I hardly moved. Sitting on my bed, I let out a deep, slow, guttural wail. I wasn't simply emotional or weepy, like I had been told I might be. This was something quite different. This was a sadness of a shockingly different magnitude. It felt as if it would never go away."