Fiore -- decouple any self-judgment or self-validation from your work and its results, and stay focused on the task itself and why you want to finish it. "Lower the board" (see the link [0]) and avoid pressure messages to yourself like "have to" or "should" and focus on rational choices by committing to a schedule of your choosing that intentionally includes "unscheduled" time to relax and recharge.
Pressfield -- anthropomorphizes the concept of "Resistance" as an enemy that needs to be respected as formidable and systematically destroyed. It comes in many forms -- for you it seems like it calls itself "Anxiety" and is possibly attempting to transform you into a pod person. It is merciless and comes from both within and without. But once you can identify its attempts to derail you, you can approach the war with discipline, structure, and professionalism, and thus choose your battles with it intelligently, recognizing Resistance for what it is -- the hodgepodge collection of bricks forming the last wall between you and the choice to become who you already know you are.