Catherine didn't know how she was going to get around this. He was going to dig at her until she told him everything, all her secrets would be revealed. She didn't want to tell him, because she knew that there was a slim chance he felt the same way. "Nothing is wrong Grissom." she said stubbornly, with a weak cracky voice. She knew that he would press further, and she desprately tried to think of an excuse.
"Grissom, did you or do you have feelings for someone who doesn't have them back? That's the situation I'm in okay? I've been stressed out all day because of it, and nothing is going to make it any better."
(I'm tempted to use the 'ol "sparkle in the eye" bit again lol)