I had the baby blues with #1, and some real issues with my birth experience (emergency c-section instead of my planned natural birth, post-partum preeclampsia & bedrest, breastfeeding problems). I remember sobbing at night, struggling with how to reconcile this drugged-out feeling I had from birth. Plus dealing with a newborn, etc.
#2, I had a beautiful, surprising VBAC after 11 weeks of bedrest for preeclampsia. I was on such a high after the birth (apparently a euphoria after birth before PPD is common). I immediately started running about, doing everything I couldn't before, juggling the baby and my toddler, cooking, cleaning, etc. Even hosted my entire extended family for DS2's christening at 6 wks post-partum. All while renovating our house and living with my dad. Ugh. I was so stupid!
Found myself unable to do anything, to think straight. It took 80% of my energy just to put a smile on my face for my kids. I couldn't sleep, and started to want to hurt myself just to feel something. All I could feel was sadness, anger, and disappointment - the happy feelings were completely muted. Called my MW, she referred me to a psychologist and prescribed an SSRI.
If you think you have it, you probably do. The three pronged approach is the most effective at treating PPD - medication, therapy, and exercise. You need all three to get the best results. I am now weaning off of the meds (I was switched to Celexa b/c of side-effects I had on my first SSRI) and am still breastfeeding my now 10 mo old. Most docs do not understand breastfeeding & antidepressants, so go in armed with info from Kellymom.com
You can do this - it is like wearing sunglasses all the time - you don't know how bright it really is outside until you can get them off!!! Good luck --