Most Helpful Guy
Don't obsess over it. It's over, just let it be over. Mourn for it, but don't spend too long mourning. Don't think about getting back together, don't stalk his Facebook, don't obsess over whether he's found someone new, don't obsess over whether he ever really had any feelings for you. These are all pointless.
Work out what lessons you can learn from it. Remember that you still have friends. Spend more time with them.
Also remember that the next time you're dating someone, not to let your friendships go by the wayside just because you are seeing someone. Friends are important to help you pick up the pieces when the relationship fails.