Socialite and model Lydia Hearst has been was hospitalised with kidney stones.The 23-year-old daughter of publishing heiress Patty Hearst was taken to New York Presbyterian Hospital on Tuesday in severe pain.In a post on her Facebook page from hospital, Hearst wrote, "Today may be the worst day of my life." She added on Wednesday, "Another day, another drama. Kidney stones are the worst."Hearst's representative confirms to Star magazine, "She has a problem where she gets kidney stones which are incredibly painful but not a health risk. She went into the emergency room on Tuesday and they kept her overnight."The publicist insists Hearst will be back on her feet in time to walk the runway at the Tommy Hilfiger fashion show in New York on Thursday.