After being diagnosed with stiff-person syndrome (SPS) in 2022, Celine Dion knew she had two choices: “Either I train like an athlete and work super hard, or I switch off and it’s over — I stay at home, listen to my songs, stand in front of my mirror and sing to myself,” the singer, 56, said in a new interview with Vogue France. “I’ve chosen to work with all my body and soul, from head to toe, with a medical team. I want to be the best I can be.” Celine is currently undergoing athletic, physical and vocal therapy five days a week in the hopes of, one day, returning to the stage. “It’s hard,” the six-time Grammy winner confessed. “I’m working very hard, and tomorrow will be even harder.”…