Stuttering is a PHYSICAL REACTION to a MENTAL stimulus: anxiety. When you think you are going to stutter, you get anxious, which makes you stutter. Stuttering causes anxiety, not anxiety causes stuttering. Work on your speech. Slow your rate, breath better, stop clenching your jaw. Research breathing via diaphragm. Another common cause of stuttering is hard onsets to words. Most every stutterer tries to "puke" out words by stressing the first syllable of every word the hardest. Normal, fluent speakers stress the middle syllable of words and start/end with soft articulation. It's a lot to take in, but it's truth.