What goes in a boy mind when a girl doesn't reply to his IM...twice in a row.?

depends how well you know each other i would say. I personally am in the middle of trying to get this girl i like and when i send texts and she doesn't reply i don't really know how to handle it. i think is she busy and if i don't hear from her in a long time after i kind of get sad :( i would just talk to him i know i feel great when i get to talk to her again :)