I think it means that he is taking into consideration that he may be wasting his time trying to be with a girl that left him. He doesn't really mind the situation unless she tries to leave out of his life for good. That is when it all comes flooding back to haunt him with everything she ever said that he meticulously analyzed down to the words she used and even the letters.
Then the last part i think he is comparing life to a car sinking into a large body of water and he is starting to realize that death is eminent as the waters rise over the windows and all around the car. (almost like the winter time simile to getting old in life) Then he starts to show that he really does want to be more than friends with that girl again and hopes all his efforts were not foolish.
I think it means that he is taking into consideration that he may be wasting his time trying to be with a girl that left him. He doesn't really mind the situation unless she tries to leave out of his life for good. That is when it all comes flooding back to haunt him with everything she ever said that he meticulously analyzed down to the words she used and even the letters.
Then the last part i think he is comparing life to a car sinking into a large body of water and he is starting to realize that death is eminent as the waters rise over the windows and all around the car. (almost like the winter time simile to getting old in life) Then he starts to show that he really does want to be more than friends with that girl again and hopes all his efforts were not foolish.