I figured this out when I miscarried in December... even though I didn't carry my baby to full term, I still suffered from post partum depression (on top of all of the horrible things I felt at having lost my child). Post partum depression is due in major part to the loss of the placenta which contains huge stores of hormones. With the very sudden loss of these hormones, I felt like I wanted to die. My mate, Jay, had a very difficult time with it as well... if the father is involved in your life, he may feel a sense of loss as well -- talk with him about it.
I used a lot of herbal extracts, teas, and essential oils to help balance my hormones, and talked a lot with Jay and with my parents. It was the most empty and painful experience of my life... but if I hadn't had anyone to talk to, I don't know what I would have done. It really helps a lot... someone you know and trust, or ask someone to refer you to a counselor. Sometimes college campuses or women's centers offer free or inexpensive counseling, and there are also support groups you can attend. Call your local hospital and ask them to refer to you a miscarriage/stillborn/loss of newborn support group.
I was sure that somehow it was my fault, and I spent a lot of time trying to figure out what I did that made it happen... but I decided (and I still struggle with feelings of guilt) that the time that Jay and I got to have with our first was worth every second, and I woulnd't undo it for anything. I learned so much about myself and even got back in touch with my spirituality, let go of a lot of anger towards God, and allowed myself to ask for help. Don't be afraid to ask for help, whether it be from spiritual guides, friends, family, community. I'm very sorry for your loss, and I wish you all the good in your recovery.