Make the appointment and then print out or write out what you have written in your OP if you think you will struggle.
If your DH starts to say its something you can fix yourself you need to tell him that it is hormonal, it is because your body has been through a major event, and that you need his understanding and support. If he still judges then you still need to carry on and seek the help and support from the GP.
It definitely takes a while to get used to. When I had DD1 I did feel instantly in love with her, but when I had DD2 I couldn't even look at her for the first hour. I let her do skin to skin and then made DH take over. It was definitely a few weeks before I got used to having a new person around, with them both.
I had severe PND after DD2. I was fine until she was 16 weeks and then it just got worse and worse. I wish now that I had spoken to someone at the start, instead of suffering for nearly a year.
My DH forgot DD2 when he went to get petrol, and left her in the shop beside the fridges. He put her down (in her carry car seat) to lift something into the basket, and then walked all around the shop, paid, and was on his way back to the car when he remembered. :o
I know its not quite the same thing, but it is a HUGE adjustment and it will take time.