I think you should see a speech therapist at your school. Most schools atleast in the US have them. It probably won’t help with the bullying but it will help with the speech. They’ll teach you good techniques. Now as with the bullying, you gotta stand up for yourself, I don’t mean start fighting. But people usually only bully easy targets, people who just take it. Even with a stutter you’re still yourself. You gotta own it & show them it doesn’t bother you. Even if it really does.