postpartum depression

Who should I talk to about how I've been feeling? I was talking to someone about everything that's been going on and my dad and they both said it sounds like I could be going thru PPD. Woukd jt be something I brought up to my OB? Should I make anappointment with her to see her before my 6 week postpartum visit? My anxiety is thru the roof. Harper is 3 weeks old today and has been home a week tomorrow. It's not just having a baby in the house that's making my anxiety the way it is because even if I'm not with her it's horrible. I can't sleep. I either can't eat or that's all I can do is eat. I'm already 6lbs BELOW my prepregancy weight and have been for about a week and a half. I just want to be the best mom I can be for my daughter. I love her but I honestly just feel like I'm going thru the motions. I feel like I haven't bonded with her and i don't know if that's because she was in the nicu for two weeks or if it's just because I'm feeling off. All she does all day and all night is SCREAM. and it's wearing me so thin because I can't do anything for her. We don't know why she screams and cries like she does.  When she finally goes to sleep and I doze off and I hear her cry I just want to cry.  I get so frustrated. I just need to know who to talk to.