Like everyone else says, this too will pass. I find when I get more sleep I stutter less, when I am more confident I stutter less and when I am relaxed I stutter less. Try to see if you have a problem with any of those things and get more sleep etc. I am 35 and stutter a lot less then I did as a kid and I'm sure you will too. High School ends and you will never see most of those people ever again so focus on your goals and let your teachers know about your speech impediment before class so they know your issue and it's not that you don't understand or are not wanting to participate.