SOMEONE HELP ME OR I WILL DIE

*Hope is unusually surprised*, your story gave me a sense of deja vu. Like you, i fell in love with someone at school and i asked her to the prom/formal, and i got rejected too. Moreover, I also only see pros and no cons against her as well. Furthermore, she is the nicest person i've ever known and it hurts that i am not with her too.
But, the main difference is that i asked her to go to the formal with me 10 months ago. I guess i am in one of the best positions to help you.
Hmm... seeing he said that 'he wasn't interested,' could indicate he doesn't want a girl friend right now or he has someone else in mind or he wants to concentrate on his studies. He can always change his mind but in the mean time, speaking from my experience, you should take it as a 'No' forever. I know that sounds cold, but maybe you could avoid the mistake i made, which was waiting and hoping that the girl i like would change her mind. The reason why i waited was 'cause she said that "she didn't know me," so i thought she would change her mind, but in reality, i was waiting for nothing, but my untimely demise. Nevertheless, from waiting, i became distracted from my studies and i may have jeopardised my chance of a prestigious career. Moreover, i drifted away from my friends and i couldn't sleep, but worse, i was highly suicidal.
Thus, listen to me when i say, concentrate on your future and don't let him distract you from living ur life the way it deserves to be lived. I don't want you to lose everything in the end.
After several weeks, the sharp pain will turn into a dull ache and eventually, you will begin to feel more content with life. Time will help guide you through this ordeal. Next, you should talk about how you feel with someone close like how u did with the posting of ur story. Trust me, get everything out of your chest, it really helps.
The problem now would be trying to get him out of ur mind. This must be one of the hardest challenges in life, but the process could take a few months or literally, a few years!!! It depends on ur view of him and how deep ur affection is for him. I'll keep this short, but the main thing is to avoid contact with anything that reminds you of him. Now, i know that is EXTREMELY difficult, especially when you see him everyday at school, but you have to try 'cause if you always think of him, you are ultimately trapped and you will feel even more depressed as you will replay that rejection over and over again in ur mind. Put away photos of him into ur drawer and avoid seeing him around in the courtyard at school. I know you want to see him 'cause u love him, but you have to resist the temptation. Remember, he may be your first love, but he won't be your last!!! Before i go, don't do anything impulsive like committing suicide, ur dilemma is only temporary!!! I am living proof that life can get better.
From the bottom of my heart, good luck and take care!!! 8)