I feel like I have high anxiety I sometimes hold my breath without even knowing and I studder why?

See a mental health . Seeing mental health therapist to understand the origin of this problem and learn techniques to deal with it is the correct approach. Sometimes medication in conjunctiion with therapy can be helpful . This can be prescribed by your physician or by a psychiatrist who can also work with you in therapy.
Consider speaking . With a psychologist. They can help you reduce the anxiety and understand the origin of your symptoms.