Hey girlie,
I am new here but saw this popping on my screen so might as well answer it lol.
Well let me tell you something, you tried all you can to apologize, tell him you want him back, etc. and sorry to break it to you he does not care about you. The only way to make it better is to just accept that its over, life goes on. You will find someone better in the future, and right now it may seem hard since he is your first boyfriend, but trust me someday you will get over it. You're a young beautiful girl, so focus on yourself. Many women tend to get clingy in a relationship when they lose themselves in that relationship, and make the guy a priority. I deal with my girlfriends going through this all the time. SO keep your chin up and stay strong, ignore him he is not worth it! Good luck! :)

I know it won't stop the hurt, but if he can't listen to you and forgive you, it's over. And I'm seriously not trying to be rude, but it is your fault, and it might help if you wrote a letter to him(however 6th grade it sounds) and tell him what and why you did it, and apologize again. But don't sound desperate or needy- keep it business and simple, not mushy, because that'll probably drive him away. But in a letter, he has time to think and sort his emotions before telling you know, plus it's a lot easier to organize your thoughts on paper. And you might love him, but I love my cat, and I love my house- maybe you have more of a nostalgic, desperate love for him too. And I'm not saying that's true, or assume what you really feel- I'm just trying to have you see the situation in a different way. I'm sorry if this hurt your feelings- good luck!