Last night, Serena Williams opened up about how ‘postpartum emotions’ have her feeling inadequate as a mother. In her latest Instagram post, the 23-time Grand Slam champion shed some light on why she withdrew from the Rogers Cup, an annual Canadian tennis tournament.

“Last week was not easy for me. Not only was I accepting some tough personal stuff, but I just was in a funk. Mostly, I felt like I was not a good mom,” Williams wrote. She credited the feeling of incompetence to postpartum depression and revealed that she often talks through those moments with other moms, including her relatives and close friends.

The four-time Olympic gold medalist stressed how little time she gets with her daughter, Olympia. “I work a lot, I train, and I’m trying to be the best athlete I can be. However, that means although I have been with her every day of her life, I’m not around as much as I would like to be.”

Williams acknowledged that moms, despite social status or career choices, experience these feelings. “Most of you moms deal with the same thing. Whether stay-at-home or working, finding that balance with kids is a true art.” She decided to take time off to sort out her personal stuff.

Last year, the 36-year-old gave birth to her daughter after an emergency C-section on Sept. 1. She developed complications during labor, including blood clots in her lungs. The tennis champion has been vocal about the difficulty of pregnancy and childbirth. She’s not alone. Beyoncé has also spoken about the emergency delivery of her twins, Rumi and Sir.