Writers can relate to this resistance to practice. Writers know very well that you must have the discipline to show up everyday and write, even if what you write is terrible. The point is to show up. Buddhists use this term as well, when talking about meditation practice. We can resist sitting on the cushion, telling ourselves we don't have time, but if we commit to 5 minutes, it is likely we will end up sitting longer. The same is true for all creative practice.
I have anxiety about songwriting. I also fear my own songs. I worry about sitting at the piano, because of the disappointing and impending doom of having to eventually get up and fulfill my other responsibilities. That is the problem of not being present, and the anxiety is really about my fear of failure, my fear of writing embarrassingly awful melodies and singing borderline cliche's. All of this rumbles through me at about 10:30 every morning as I anticipate my 11:00 start time for practice. I have dealt with this for years, and yet, I still manage to write songs that are okay, and despite my intense fear of failure, my voice continues to improve. This is why I say you have to show up first.
I am very hard on myself. I still think I could be a better songwriter, and my fingers could flow over the piano with more ease, my voice could soar with less effort, I could tear up the guitar with better solos, but for now, I just need to relax about showing up.