Short answer: Shut up and start. Just start. Now.
Longer answer: I feel your pain, I’ve been there many times.
Take a look at “The Artist’s Way” by Julia Cameron and “The War of Art” by Stephen Pressfield.
Both are about freeing yourself from creative blocks. The first is more gentle, the second is more forceful.
Pick the one that resonates more, order it, and read it. Now.