postpartum or overwhelmed?

how would you know if you have postpartum or are just over whelmed from no help? I have new-born twins and a toddler 17 months

and an older child who is being defiant (from a previous relationship) my so works away and doesn't help when he is home, no family around and his family makes excuses when I ask for help I can't even clean my house right now I have 2 weeks of laundry I haven't even folded I've been basically digging baskets and the dryer for clothes as needed, I feel like my toddler I don't have enough time for him and I can't get him to stop being over bearing with the babies I can't get him to be easy or not jump around them if the are laying he will try to climb into the swing with them or swing it he's not jealous he just insists on "helping" he throws things and almost hits them constantly my older child won't help when asked to do her chores she will pretend to do them when I check and it's not done I will make her re-do it and she will mouth and fight me telling me it's not her job she is slamming doors and stomping both babies are in the same schedule and want fed at the same time which is hard to do alone I try to prop bottles but the either let it run out their mouths won't drink or gag on it the whole time and the whole time I have to fight my toddler to stay back. I've been pumping my milk and it's hardly coming in at all it was doing real good and now all the sudden it just stopped I'm almost dried up so that has me stressed out I can't understand why it stopped they don't do good on the formula so I have to keep pumping but I'm not making enough to feed them I have been getting very little sleep and just feel so over whelmed I have been hollering way to mu h and ot makes me feel like a bad mom I have been crying frequently during the day and night is this depression?

I can't afford to hire anyone to help and I've tried to get my so other to help when he's home but he always finds some reason he can't , I literally have no one