Kaia Gerber revealed her struggles with “disordered eating” and being “jealous” of her supermodel mom, Cindy Crawford. “I’ve had disordered eating in my life. People are like, ‘You look terrible,’ and it doesn’t exactly make you go, ‘Oh, good. Let me get over this mental illness then!’” the actress told Vogue for its Tuesday cover story. “Negativity has never saved someone’s life.” The “Shards” star admitted to feeling pressure around her body image due to Hollywood’s thin craze and public scrutiny. “We’re clearly in one of those cycles right now where people are very, very, very thin. As someone who’s been thin most of my life, I’ve…