That happens to me as well. Anecdotally speaking I have pushed beyond my comfort zones. After years of avoiding social interactions I now engage more often. It's helped me so much in recent weeks. I know it's daunting but you have to at least try. Keep your head and keep things in perspective. A speech impediment is a daunting aspect of your experience. It will more than likely be a part of you for the rest of your life. But when you allow it to define you that's when life will never be fulfilled.