I actually am having a similar experience. I had a great pregnancy and birth experience and now I feel like my whole world is collapsing. Previous to this, including my entire pregnancy, I don't think I ever cried once. In the past two weeks I have broken down in front of every single person that has come to my house to visit.
I, too, have had problems with breastfeeding, although I cannot say that I think this is where most of my anxiety and depression lies. I was trying to 'wait it out' a bit, but my husband saw how miserable I was and asked me to call my OB. I have an appointment Monday. My best suggestion is to ask for help! I spoke to a nurse who called my house to see how I was doing. I asked her if she thought it was too early, and she said it's never too early to get help when you are not feeling well. Just the fact that I have an appointment on Monday is getting me through the weekend.
I hope you feel better soon!