Crippling self-criticism.

[Gamma-UT]

Deliberately make the worst sounding song you possibly can. Pick the worst, most annoying and obnoxious sounds, melodies, and chord progressions.

<Insert obligatory Skrillex gag here />

Alternatively, just pick really bad sounds - think early 90s General MIDI rompler grade - can help a lot in honing melodies, beats and progressions before moving to production. If it vaguely works on GM sounds, it will kill on stuff that sounds a lot better. Composing on good sounds lets you settle for "good enough for now".

[DrGonzo]

I'm definitely in favor of experimenting to break out of a creative rut.

Try shooting a video and then score your music to the video... Now throw away the video and keep the music.

Make a song in an unrelated style. How about polka? Try combining two unrelated styles.

Deliberately make the worst sounding song you possibly can. Pick the worst, most annoying and obnoxious sounds, melodies, and chord progressions.

Collaborate.

Oblique Strategies
https://en.m.wikipedia.org/wiki/Oblique_Strategies

Making Music
https://makingmusic.ableton.com/

All good advice here, especially the Making Music book.

My personal creative block just got unstuck by something as trivial as a Korg Volca Sample. This thing is almost a toy. But I can't stop making cool ideas with it. The workflow is extremely fluid. It's so damn amazing I just bought a second one

/C

[woggle]

re creative block - I can't really play guitar so much anymore as I have developed arthritis in my fingers but... that had me make some pieces for guitar that only use different ways of bending strings and never move the fingers around - whammy bar in usual way, bend with finger behind the finger that is fretting, bend with finger that is fretting, bend using heel of palm on whammy bar plate. I was very happy with the results. Constraints can be very inspiring

[Ed A.]

Some people just don't want to go through the angst of creativity anymore. I know that Captain Beefheart completely walked away from music in 1982 and had not done anything musical ever again.
Peter Baumann from Tangerine Dream sold his Private Music label to Windham Hill 20 years ago and got out of music completely. He founded the Baumann Foundation in 2009, a humanist organization that has nothing to do with music.
Maybe it's time for you to move on to something less anxiety inducing.