The best thing to do is to confront your fears, do things that take you out of your comfort zone. It’s the only way that you’ll get over your fear of stammering is to face it. I did the same with making phone calls - I avoided it for so long. I began speech therapy at the beginning of this year and I make at least ten a day at work now, plus my own private calls. You’ll get there, have faith in yourself and don’t beat yourself up if you have a bad stammering day, it happens to us all, no matter how far into our journey of becoming fluent through practice we are 😀