She already knows you care, so don't give away anymore of your energy by telling her. It won't accomplish what you want it to. Yeah, being with somebody for a long time and then being rejected by them, completely, is a hard thing to take...I know.
My advice to you is to continue to detatch. That doesn't mean giving up...it simply means letting go of the outcome.
"Always go straight forward, and if you meet the devil, cut him in two and go between the pieces." - William Sturgis, clipper ship captain, 1830's.
