Mental and emotional wreck

I seriously don't know what to do or how to cope with my mental and emotional health anymore. I am home literally every single day all day long with my 8 month old son who has temper tantruns nonstop while my boyfriend is at work. He doesn't take a single day off to be home with us. The days he does have off, he spends spends doing whatever he wants or with his friends and rarely makes time for us. My emotional and mental health is deteriorating I'm overwhelmed I have no friends or family that live near me. I can't work because we can't afford day care. I was supposed to go to school but my car broke down and and it's too far away to afford gas and I can't find a sitter for my son. We live with my mother in law and and she's home 3 days a week. She never really seems to want to help out with her grandson. She sees how emotionally overwhelmed I am daily and how depressed I have been but she doesn't offer a hand to help. She goes out all the time but she doesn't offer to take us with her or watch him so I can have my time for me. I've been begging my fiance to be home more at least one day a week so I can have a break. All my son does is cry all day long if I'm not holding him he never wants to play with his toys the second i put him down he throws himself around screaming hes been hitting me and laughing. He won't go down for naps, he's been hard to deal with lately. On top of him being hard, I also can't get any house work done because I'm dealing with him 247. I'm so overwhelmed with daily chores and not to mention I have no time to watch TV or relax I don't have any time with my friends I don't ever get a chance to go out and do anything.. My fiancee's work truck recently broke down so hes been taking the car I have now to work everyday so I never a chance To go out and get things I need for myself or groceries so we have literally no food in the house and I have no money because I'm not working so I can't order anything . I've asked him before to order some food for me and he doesn't want to do that because he doesn't want to spend money. I literally broke down crying to him about how hard it's been and how I've been feeling. I've been crying out for help to him call my mother in law, my mom, my sister.. No one seems to understand how stressful it really is. When I express these feelings to my fiance he will just tell me to get over it and that I'm a mom and that if my sister can do it then I can do it and always compares me to everybody else. He always brings up how hes stressed out at work every day and that I should have nothing to complain about. It's a lot different when you're stuck at home 247 by yourself for the screaming Baby. That's not comparable to anything else and I don't know why he always compares me to Everyone else's situations. I'm severely depressed. Irritable, hungry, overwhelmed and emotional and no one wants to listen.. I feel I've tried to cry out for help and it's not getting anywhere .. everyone always says if you're suffering postpartum depression or need a break or help then reach out. I've tried that and it doesn't work. I'm just lost at what to do. I have literally no life outside of "MAMA."