Feeling Alone

So, I gave birth to my son a month ago. My fiancé helps calm him down when he's crying and he puts him to sleep sometimes, but I just feel like he doesn't spend enough time at home with us. He has to be at work around 2am everyday. When he gets off, he has company or he leaves the house. He stays gone for hours and I'm stuck at home with a 7 year old and a newborn. My 7 year old daughter assists me a lot when I am trying to do housework or take a shower. She LOVES helping but it's not her responsibility. When he gets home he often falls asleep because he has been up so long. That leaves no quality time for me. I feel alone and stuck....kinda depressed. I know he's young (6 years younger than me) so I try to take that into consideration. I know I'm not the only one who feels like this.