Quote:
I am going to assume that you both go the the same school or somthing because you will be seeing her again at a lecture on Monday. Instead of giving her a big hug and telling her that you missed her company, you want to do the exact opposite. Make a point to talk to her, but open other people (especially girls) around her and make her jealous. Basically, do a minor freeze out. Telling her that you miss her and making big displays of affection can been seen as creepy, or even desperate. But just saying a few generic things to her and than going to hit on the other hot girls in the room, she is now in a position where she has to earn back your attention.
You have to be willing to lose her for this technique to work, but if executed properly, she will more than likely come back to you since she is no longer the center of your attention.
Listen to this guy, don't make yourself look desperate or starving for her attention. It's her that has the pleasure of spending time with you and she didn't, so be energetic and friendly with everyone but still acknowledge her, otherwise it'll look a pathetic ploy.