Our bungalow was still dark when my cellphone rang at 5 a.m. My husband and I had escaped for a much-needed yoga retreat on the remote island of Koh Phangan, Thailand, when I got the phone call no parent ever expects to get — a call that four years of medical school, three years of pediatric residency training and 15 years of practicing pediatrics hadn’t prepared me for. At the sound of the middle school principal’s voice, my heart started racing.