Reverse Cycling

Hi mommas. My daughter is three weeks old and shortly after she cleared her jaundice she hasn’t slept more than 2.5 hours at night. It’s killing me. She’s so quiet and calm all day and is a bat out of hell at night. She’s grumpy, hungry, fussy, you name it… During the day I’m making sure to stay on top of her feedings and keeping the curtains open and lights on. We have a bedtime routine with her already too . I’m trying all I know to correct her schedule. Needless to say I’m not sleeping and I have three other kids- 5, 3, and 1. And they’re all sick. I’m worn out mentally, physically, emotionally… Any advice? My boys never had this issue. She is by far my most difficult newborn. Help!!