Well, first

I would make an appointment with a therapist/psychiatrist that specializes in ppd. If you can't find someone that specializes in ppd, then I would just make sure you find someone you like and trust.
Depending on your symptoms, you may want to consider medication. There are a lot of meds that are safe to take while breast feeding. I just started taking meds and I realize now that I avoided the ppd diagnoses when my son was younger because I was scared of taking meds and bfing. Now I know that they are safe and I wish I started taking them sooner.
Having a new baby is such an adjustment... anything that you can do to start taking care of yourself would help. Exercise is one of the best things you can do for depression. Self-care... like getting a pedicure, haircut, etc might help your self-esteem. A wonderful book is This Isn't What I Expected

vercoming PostPartum Depression by Karen Kleinman. I have been reading it when I"m feeling really bad and it helps a lot.
PPD is an illness that is treatable.
Hope you find the answers your looking for...