Do you procrastinate?
I used to, and it comes up in therapy a lot as it increases anxiety and lowers mood - but we can change it!
We procrastinate to avoid feeling pain, but often, the pain of not doing something is worse.
Try this: Close your eyes and imagine yourself having already done the thing. Really picture it! How does your body feel?
Now imagine not doing it. How does that feel? Do 30 seconds for each.
Let your body tell you what it knows. Now start, bit by bit, it will soon flow.