Amber Heard is putting the past behind her for the moment. The “Aquaman” star, 36, is “doing okay” after a Fairfax County, Virginia, jury ruled that she defamed ex-husband Johnny Depp in a 2018 Washington Post op-ed, but needs to focus her energies elsewhere, a source told People in this week’s issue. “She feels drained and exhausted after the trial,” the insider told the outlet, adding Heard “is trying her best to have a positive outlook.” Heard, 36, was sued by the “Pirates of the Caribbean” alum, 59, for $50 million in relation to the op-ed, in which she identified herself as a “public figu…