Please don't feel so down. LIke you said, you both were prepared for the worst. Nothing we say or tell you to do will take away your heartache. It is very true when they say that "time heals all wounds." You will just have to have a very strong belief on that. For the meanwhile, it is best that you try to keep yourself distracted in other things. Take up full-time activities, gymming, book club, volunteer work in the evenings, makeup/ cooking classes.
It all seems futile but down the road when you look back you will realize that it was really not all that big a phase in your life as you thought. You and your thoughts, and your hopes probably made it bigger. If he's your classmate, then chances are he's the same age as you. I personally believe that it's better that you get to spend your life with someone who's a little older. Guys are always way behind on the maturity level when it comes to comparing them with a girl their own age.
With all this, just put up your shoulders and accept the fact that DESPITE all you felt for him and all you were willing to sacrifice for him, he told you he didn't want to be with you. The sooner the better. So you know what, move on, you dump him back.. in the river!!!!!
Let your parents do all the thinking for you for a while. Meet your prospects, you might want to dislike them all in the beginning, but remember that all these guys that you meet are willing to "marry". Which means that insha'Allah when things work out for you with any one guy, he will be willing to give his all for YOU. Always remember, it is more important to marry someone who wants to marry you, as opposed to someone you want to marry
He will always keep you happy.. you wont have time to think about your past... it wont even matter then!
We will all pray for you. Be strong and just stop thinking abt ur past. (atleast tr not to..)