Years ago when I was a teenager and way more religious than I'm now, I talked about my stuttering with a priest during my confession. He told me that perhaps that's a gift, so I can listen to others more. And it sounded more like a lottery than something designed specially for me: earth need different kind of people, so be a listener. As hurtful as his recommendation is still way more kinder than what's your mother said. I'm sorry you're going through this and I hope your new therapist will help you