I understand completely. It's happened to me, except it was in person with about 15 people around a table taking turns to read in Bible Study. Who knows, the others probably know your stutter or having difficulty reading - lots of people do. It's something that you'll have to work on ; which is different for everyone who stutters. Relaxing your jaw, relaxing your mind, using soft contact and easing into the vowel. KNOW that you can do this, having confidence that even if you stutter, so what. You know that, right? We're not perfect