Postpartum

Has anyone had postpartum start as late as 6months? Is that even possible? I know that nothing in my world has really changed and I should be so happy....but I’m so miserable and alone. I mean,I’m holding it together with him and then I’m falling apart alone. I don’t have anyone I can go to. I have friends but I just can’t. My husband is great....but he just couldn’t understand.....I feel like I can’t breath...I never thought I’d be the person to have “those”thoughts .....but I am. I don’t know what’s happening to me.