Post partum depression?

Can you get post partum depression after 3 weeks? I'm not sure if I have it or not.. the last week IV been so mad at my fiance for no reason it's like I wake up mad at him or don't want to be around him. I start unnecessary fights with him. And he does nothing wrong. I don't want to leave the house especially with my son. I get such bad anxiety thinking about it. I barely like to leave the house without him. I eat constantly, like I over eat so much junk food. I just feel off, like I'm sad for no reason or just irritated also for no reason..