I’m sorry this happened—it truly sucks. This has been my entire school experience from elementary school to university. I grew up at a time and place in which teachers would test students by having them answer questions for 20 min in front of the whole class, so this was my weekly or biweekly experience for all my formative years. As a blocker, it was always awful for me and, frankly, traumatizing. But that’s life too, and I think this experiences make us stutterers more self aware than most people. And please remember that your embarrassment is NOT matched necessarily by judgement from the audience. Times have changed, and I found most people are sympathetic. It’s a big chance for you to be kind and love yourself regardless.