I know how that feels. As a fellow stutterer, I've been hit many times with the "did you forget you name" and then the laugh and I will admit it hurt. Many times if not always the people don't know that we stutter and they genuinely don't know what is going on because meeting someone who stutters is quite rare (besides my family I have maybe only met 3 other people who stutter and im 24 now) so I try to not get upset or hurt because they honestly didn't mean it and are just trying to be humorous as most people try to be. Try your best to let it slide and always remember who you are. We might not be able to express ourselves to the fullest and show people who we really are but you never forget who you are. Stay strong. We're all gonna make it.