You won't forget her for a while...
But it doesn't mean you shouldn't be a happy person to the people around you. Tell them what happened, and I think your true friends will begin to appear before your eyes.
Stay with them, they know how to get you through it, and who knows... One day you may look across the crowd of people and breifly see the world looking back at you in her eyes... but at least you will have built up the stength to turn away.