I Died Seven Times

My name is Chen Mo. On my 28th birthday, I received a strange text message: "If you receive this message, it means I am dead." Three hours later, police discovered a body in an underground parking lot. The deceased's face looked exactly like mine. What's even weirder is that he is holding a coin with the number "7" engraved on it. I thought it was just an elaborate murder. Until I found out about an experimental accident fifteen years ago—— My name is clearly written on the death list. Age: 13 years old. From that day on, more and more "memories that don't belong to me" appeared around me. One woman told me: "You're not supposed to remember this." A person who looks exactly like me told me: "You are no longer the first me." And I finally discovered that there had been seven "Chen Mo"s in this world. They all think they are real. And now, it's the eighth's turn. The problem is—— If all seven "I's" are true, So who am I living now?