Spend some time looking at your work process: at how much time you’re spending on your dissertation and when, at exactly how you’re writing. (Are you trying for a final draft each time you sit down? Is it working?) Look at whether the process feels efficient. Particularly examine how much you’re reading. It’s more common for the students I’ve worked with to read too much than to read too little. They use reading as a distraction, or as a way to avoid having to think their own thoughts, or as a magic charm: “If I read everything in the field, then I’ll be able to write and be sure I haven’t missed anything.” Relax. You’re sure to miss something, and it’s very unlikely to matter much. It may make you fell very rigorous and virtuous to have read every article ever published on your topic, as well as related ones, but it won’t help you finish your dissertation. Bite the bullet and get back to your own writing, and your own thinking.