Beyonce is an unstoppable force of nature, but in a new documentary she reveals one of the most heartbreaking moments of her life. Her upcoming self-directed documentary Life Is But A Dream allows the singer to talk, unguarded, about an early miscarriage she had before the birth of her daughter Blue Ivy. Said Beyonce, ”I went into the studio and wrote the saddest song I’ve ever written in my life. And it was actually the first song I wrote for my album. And it was the best form of therapy for me.” The documentary, which will air on HBO February 16th, actually looks amazing as Beyonce presents a new level of honesty for fans, which is also at the same time, carefully constructed. In other Beyonce news, new footage of the singer rehearsing for her big Superbowl performance has appeared. The trailer is called “Countdown to Touchdown” and is set to her song “Countdown.” Watch it below.