Son is refusing to sleep

My son is 12months old. He's going through a cycle where if my husband isn't home, he's blatantly refusing to sleep. It's been over a week now and he's been refusing his naps altogether. I'm so mentally, emotionally, and physically drained. I have no one to help me, no family, no friends. I've tried my best to keep a schedule, and routine to help him understand when it's time to rest. Blackout curtains, sound machine, comfy pajamas, turn down the thermostat. It's just not working. Today I've been going back and forth trying to get him to sleep for over five hours. I have no time to eat. No time to shower. No time to live. I'm dealing with PPD and have had no luck with medication or therapy. The lack of sleep is making it much worse. Any time I try to put my son in his crib he immediately flails and screams the moment I gently let him go. What ensues is screaming until I give up and let him play with his toys. If I'm not sitting right next to him he will continue screaming. I can't get any sort of break or moment of decompression. I've been listening to him scream on and off for about 9 hours today. I don't know how to get him to rest. He is clearly very tired. He's fed. He's wearing a fresh diaper. Every necessity is met. He doesn't do this when his father is home. I don't know where to go from here. He is making me completely miserable. Is there something I'm not trying?