Im lonely and I hate it

Ever since I had my son for months ago I’ve been off and on miserable. Tonight is really bad. My fiancé goes to sleep at 6 pm after waking up at 8 am, he does this kind of thing all the time, and I understand he’s tired but I feel so alone whenever he’s not with me. When he goes to work all I do is wait for him to come home. All he does is get mad when I ask him to stay awake a little longer with me, he says I never let him sleep even though I’ve never made him wake up in the middle of the night with the baby. I just don’t think he understands how alone I feel and when I try to tell him he just tells me “nothings ever good enough for you”. I’m just so hurt right now. This is really stupid to be upset about and I thought my postpartum depression was going away but it’s not. I honestly question the point of life and feel like if it weren’t for my son I wouldn’t be here right now, I need to live for him. I think I’m going to call my doctor in the morning to get a referral to a therapist. I just felt like I needed to talk to someone and I don’t really have any friends so I figured I’d post here.