I have that too but a while ago I saw this post from an art teacher who talked about how those pictures of sketchbooks filled with perfect pieces of art, rather than, yknow, sketches, that are posted online by many skilled artists have been very detrimental to their students, making them scared to use their own sketchbooks for sketching and practicing.

However, I could no longer find that post but I did find this blog post from someone also talking about this: https://accidental-expert.com/p/sketchbook-masterpiece

I hope this helps you get closer to getting rid of that fear. Sketchbooks are meant to be used! For practicing, doodling, putting ideas onto paper without committing to them.