Feeling yourself fall into PPD

I had a beautiful perfect baby girl April 17th at exactly 930 am. She was 7lb 4oz and everything was going perfect. I was exclusively breastfeeding and felt like nothing could go wrong. She started to lose weight by day 2 and doctors tell me it's normal. By day 4 she had lost over 10% of her birth weight. Tons of test were sent out and by day 10 she was being sent to a nicu hours away because the doctors couldn't tell me what was causing my sweet little girl to have these problems. I get to see her most days and others I don't. I started crying all the time. Inconsolable really. I went to my doctor to get help. Some days I still feel helpless. I have a three year old son and a husband who works from 3pm to 2am and, my baby isn't home yet. I feel so alone sometimes. I figured if anyone the women here would understand. Sorry for the book I just have to get it out.