Need Advice from Professionals

Need Advice from Professionals Hy, I am in my 20s. I have Stutter but I figured it out myself that it is because, I can't remin calm and speak fast which leads to blockage and horrible stutter. I am doing mirror exercises and can speak very calmly and slow. But while talking to people I can't remain calm and can't speak very slowly even if I tried to do it. Please, help me in this matter.