Hey OP, I am sorry that it happened to you. I am a 26 YO stutterer and I was where you are. I recommend you going to speech therapy. Also, disclaimer works. You can say " Hey, I have a speech impediment which prevents me to speak fast, but atleast I will speak only key points for you." We stutter because we take pressure of not stuttering. It's unnatural, take that load off you. I conduct webinars for 100+ people now. It does get better if you work for it. :) nobody is perfect in this world. Don't let their laughter get to you.