You have mental blocks against people. Check my posts about EMDR. If you also try to speak long with a less air in your lungs, you will get stuck at the end. If your M Test result is about 20 seconds, you will directly fall below 15 seconds and you will be in panic. I improved my M test result from 14 to 50 and I am so insensible to most of the cases. To sum up, work on your mind with EMDR, work on your body with breathing exercises, such as Keep it costal app.