Other people's opinions about you shouldn't be the cause of your death. The fact that they're laughing about your stutter shows that they're not the kind of people you want to be around. I suffer from severe blocks while pursuing architecture major, and I give speeches during my presentations constantly. Yes, they are quite often awkward and exhausting, but I don't feel less than and certainly don't wish for a death. Please, take care of your mental health and hold on, it will get easier.