If I were you, I'd try to adopt a "who cares what this person thinks" mindset. Especially for situations like ordering food and giving them your name. I stutter on my name all the time when ordering or picking up food. But I don't really give a shit because, I'm just picking up food. And the opinions of the person providing that service really don't affect my life in any way whatsoever. And more than likely they're not even giving your speech a second thought. They may notice it while it's happening and that thought may stay with them for a brief second as they complete your order. But that's about as long as I'd expect anyone to give any thought to it. Because, it doesn't affect them.