The artist is trying to say people are thinking about their future and what they are going to be. Thinking about the future helps you to be successful to get the career you what. Being what you what makes you happy because you tried very hard.
The artist is saying that he is dreaming about what life would have been like if he and his girl didn't break up.
In his sleep, he dreams of what his future holds. The term "we" could refer to him and a girl or him and God.