Since I had a very similar experience, I can kinda relate to this situation. With that said, I think this song means that the guy and girl used to be so great together, laughing with each other over rediculous situations. Then there was some sort of falling out between the two, possibly a change in heart, and the two were began to act differently around each other. When the guy was once with the girl, he was so happy, but now it seems like he's unhappy all the time. The girl, however, seems to not really care about the situation, whereas the guy is longing for the past to be the present again. I hope this is somewhere close to the intended meaning for this song.
Since I had a very similar experience, I can kinda relate to this situation. With that said, I think this song means that the guy and girl used to be so great together, laughing with each other over rediculous situations. Then there was some sort of falling out between the two, possibly a change in heart, and the two were began to act differently around each other. When the guy was once with the girl, he was so happy, but now it seems like he's unhappy all the time. The girl, however, seems to not really care about the situation, whereas the guy is longing for the past to be the present again. I hope this is somewhere close to the intended meaning for this song.