Because you're still moping around about Kristy. That's why. I know it's gotta be tough, but you have to move on and one day you will find a replacement. It always happens.
That's true, after I broke up with my girl I was debastated, I didn't even wanna wake up in the morning for awhile, and then I met this girl, we never were abything besides friends but for some reason she made me forget about the ex.
Anyway Good luck with everything, just give it time and it'll heal.