Tennis superstar Serena Williams revealed Monday that she has been “in a funk” since returning to the sport as a new mother. After suffering a major defeat at the hands of Johanna Konta at the Silicon Valley Classic last week, Williams said on Instagram on Monday that she has been dealing with some “tough personal stuff.” “Mostly, I felt like I was not a good mom,” she said, adding that she has been feeling “like I’m not doing enough for my baby.” “We have all been there. 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. Most of you moms deal with the same thing,” she wrote, calling moms everywhere “true heroes.” Williams, 36, underwent surgery for blood clots and dealt with postpartum depression after giving birth to her daughter, Alexis Olympia, last September. The 23-time Grand Slam champion recently pulled out of next week’s Rogers Cup in Montreal, citing personal reasons.