Can I ask how old are you? I felt like this for years, all the way through school. It's really hard. But it does get better. As I got older (I'm in uni now, which is a better environment than school) I stopped caring as much about what other people think of me. And as my confidence has grown my stutter has improved. I don't have a lot of advice because different things work for everyone and you have to find what works for you. Are you seeing a therapist? A good one will teach you tools for getting past blocks and will also work with you on a deeper level to build up your self-confidence. At the end of the day you have to remember that your voice is important and you deserve to be listened to. As my mum is fond of saying: "Those who mind don't matter, and those who matter don't mind." Someone who laughs at you isn't worth your time, and that's their loss, not yours.