There is no guarantee in affairs of the 'heart' no matter what age we are. But, I think you are being too clingy and pushy, and that's why he is distancing himself from you. Could it be that you want him to 'prove' his love by giving you an engagement ring or asking you to marry him? Hey, this is unrealistic, after only being together for 7 months, and you still going to school.
You should be concentrating on your education and future and not depending on someone else to place you in the center of his universe. He has a right to get his education, look for a good career perspective, and make new friends - and there is nothing you can do about it. The only control you have is over what you do with your life and how you cope with the choices you make.
We are in the year 2008 and not in a TV show that shows you that all high-school loves have a happy end. Not even real life always has a happy end and we just have to face that fact.
So, if you want to keep his friendship and hope it grows, don't pressure him and enjoy the time with him without asking him to tell you how much he loves you all the darned time. Get real and grow up. He might be your first real love, but he won't be the last, not at this age in your life... so give yourself a break and don't be in such a hurry to come to a standstill in your life that hasn't even begun to develop yet.
Sorry if I was a little 'blunt', but you need to take off those rose-colored glasses, dear.
Life still has so much to show you, so relax and live it.