Do you feel in advance that you will stutter? Do different things happen in your brain?

Do you feel in advance that you will stutter? Do different things happen in your brain? Hello everyone, I'm trying to improve my stuttering skills. I try to speak in front of a mirror or a screen, but when I get a block, I can't get the word out, as if my brain knew it would get stuck there beforehand. Do you experience moments like this? Can you give me advice on how to get out of a block?