Michelle Williams, still reeling from the tragic death of her ex, Heath Ledger, burst into tears at the mention of the late actor’s name during a recent interview with Newsweek magazine. The “Shutter Island” actress, who is the mother of Ledger’s 3-year-old daughter, Matilda, said her grief over Ledger’s accidental overdose is getting worse, not better. “It’s so sad,” Williams, 28, told the magazine. “I just wake up each day in a slightly different place . . . grief is like a moving river.” Although the two “Brokeback Mountain” stars had split before Ledger’s death, they remained close. “It’s a strange thing to say, because I’m at heart an optimistic person, but I would say in some ways it just gets worse,” she said. “It’s just that the more time that passes, the more you miss someone.” Ledger died last January. Williams, who shot “Shutter Island” in Boston last spring, said she is taking a year off from work to focus on her daughter.