I second what a lot of these ladies said. I had very bad ppd that went undiagnosed until DS was 6 months old. At that point I moved in with my mom and she saw that things were not right. I didnt have typical depression signs and thats why dh and I just didnt identify what it was.
Not seeking help sooner is my one regret about his birth. I missed so much of his life resenting him.
Even if you have mild ppd, sometimes just getting diagnosed and legitimising the ppd helps. You can find a counselor to help you learn new coping techniques. For me those things along with 6 months of Prozac changed my life.