I'm tapering off sertraline since last week. I'm under the care of my MD. I've been having unusual symptoms since last night such as lightheadedness, nausea, "zaps" in my head, ringing in my ears on and off. In addition to these, I've been having sensitivity to bright light since I woke up this morning. I was prescribed to take Zoloft, since my PTSD diagnosis in 2007, for 100 mg once a day at bedtime. I called my MD but he's not available. I called the 24-hour nurse line of my health insurance, too, but she suggested that call my MD again. Please advise.