I'm so sorry this happened to you, and I totally share your reaction, which I had so many times. I wish people would just consider that blocks, hesitations, and repetitions are due to stuttering, but there is still so much ignorance and, even worse, so much callousness around. Personally, I made it a habit to disclose my stuttering when something like this happens: often people laugh because they do not understand what is happening, and I get some pleasure when they learn about it and feel bad (you know what? I'm glad sometimes it's someone else's turn). At times they are so busy chuckling at me they don't hear my explanation, so now I make sure they hear me. It has taught me to feel righteous anger: no longer directed at me, but at the ignorant people around. One thing that also helped (I believe) was EMDR. I did a few session on a series of humiliating events when I was little--specifically me being forced to read a poem during all Christmas recitals, as a little girl who didn't know how to advocate for herself--and noticed my reaction to people's mocking/embarrassment is a lot better. Again, there is a lot to say about "righteous anger": it's a way you stand up for yourself, internally, and put them blame where blame is due. We should not feel bad when we are mocked: it's the mocker who should feel all the shame.