I am afraid of falling asleep before my baby

Dear Delyara, My daughter is four months old and healthy. Every night, I remain awake listening to her breathe. I know the safe-sleep guidance. She is on her back, in an empty cot, at the correct temperature. None of it quiets the image of finding her still in the morning. I set alarms every twenty minutes, then wake before they sound. During the day, my hands shake and I forget simple things. Yesterday, I left the front door open. My husband offered to take the night shift, but I cannot sleep while another person watches her because what if he misses something I would notice? The health visitor called this postpartum anxiety and arranged an appointment. I nodded, thanked her, and then spent an hour researching whether the medication she mentioned could harm breast milk. Fear has attached itself to love so tightly that resting feels irresponsible. My baby sleeps peacefully. I watch her chest rise and fall and understand that I am meant to feel grateful. Instead, each breath becomes something I must personally ensure continues.