Go to speech therapy. When I was in high school my speech pathologist was able to talk to all my teachers about my problem and they never picked on me about it or called on me. Once you graduate high school you lose your speech pathologist so make sure you get an IEP which is a paper that says you may do presentations in a private setting, that way you won't deal with more of this bs if you decide to go to college. I stutter a lot no matter what I do. I don't have any advice for you on how to make it better but you could try working out three times a week minimum to help increase the blood flow to your brain. It might help your speech. The other thing to do if you're determined is talk to a guy named Lee Lovett. He helps stutterers improve their speech for free.