There is so much better advice than “just get it done” (isn’t that like telling a commitment-phobe, nobody’s perfect, so just pick someone and commit? I’m sure someone, somewhere, has given themselves that advice and taken it, with positive results, but it’s kind of questionable advice in general).
For example, “meditate” is good advice. Let the anxiety come up; allow it to flow, and leave; see it without judging it or trying to figure it out. Even realizing your problem with starting is an anxiety problem, and feeling the feeling in your body, is a huge step. Maybe noting some beliefs that contribute to it. “Journal” is good advice. Practice writing in your voice, and the act of writing. Journal about your anxiety. Learn to enjoy your writing. Practice will improve the quality. Discounting quality will not help.
Stories about how I procrastinated on something for a month and then late one night managed to forget my usual thought patterns for an hour and do it? I have hundreds of those from my past. There is some information in the thoughts I had when finally doing it (“I get it! You just do it!”), but not relative to the information you will get from going inwards and asking how to change your own patterns of feelings, thoughts, and behaviors.