I see how you're worried about accumulating more debt if you see a therepist. I think there are a few things you could do. You could call your local hospital's behavioral health or psychiatry department to see if they have or can recommend services that are free. Hospitals also oftentimes have new mom or postpartum support groups I think that are free.
Do you have any family or friends that can help you? I understand if you don't. I often feel overwhelmed and depressed and my mom is incapacitated so she cannot help me. I have another set of relatives who live across the country so they can't help. And my friends have struggles of their own to deal with.
I feel for you. It sounds like an incredibly tough situation.