hearing things

Okay so i had a miscarriage on the 11th of july.. I suffer from depression anxiety and bipolar. I handled the loss extremely well tbh.. the past few days it’s been getting me down, 2day at work i found a little white feather and went to walk past it but i picked it up and thought of my baby. Well earlier while making dinner with my bf i heard “mummy i love you” whispered in my ear in a child’s voice i swear to god! I froze and dropped the knife and cried. i don’t know if i’m going crazy or not but i definitely heard it. I’m just wondering if anyone else has had any weird experiences after a miscarriage, is it normal? i’m quite shaken up and upset but i’m not sure what to do now... i know it’s sounds crazy and i can’t believe it myself😓