"Guys, I’m just sitting in my trailer because it’s finally lunch break and I got a message on my phone saying that Banks is in her crib," she shared.
"I just watched her go down for a nap, and it’s so amazing that we have these monitors now that we can watch our babies when they’re in their rooms, but it also, like, crushed me that I’m not the one there doing that for her," she continued.
The "Younger" star also tipped her hat to other working moms — as well as the nannies who help care for their children.
"Shout out to all the working moms out there, hustling and doing what you can for your family and showing your kids what hard work and strength is. Shout out to the nannies for taking care of our babies when we cannot, for showing them all the love that you do," she said. "That’s my little thought for right now. My heart’s hurting a little bit because of my babies and working such long hours."
"I’m so appreciative to have work and have a job, but man, is it ever hard," she added.
Duff welcomed Banks with boyfriend Matthew Koma in October 2018.. She's also mom to 7-year-old son, Luca, with ex-husband Mike Comrie.
The actress's candid video wasn't the first time she's opened up about the challenges of motherhood. She called every mom who follows her on Instagram a "super goddess" back in January.
Duff shared a pic of herself sitting in her car after dropping off Luca at school. It was the first morning she'd had both kids on her own, she explained. She was "proud" of herself for having made breakfast for Luca, breastfed Banks and fed all the family's pets before she left the house.
Duff went on to say she knows she's not the only mom who hustles.
"I'm proud of every mom out there who MAKES IT FREAKIN HAPPEN," she wrote. "All day! Everyday! You are the s---! Bad ass, super goddess, world taker oner and you deserved to be praised."