What does this dream mean?

I've had this dream that i ran off with a guy. The guy was someone i was in unrequited love for 5 years. We were laughing together and we got to his house. After we we got there i ran outside and left him alone. As i was walking down the street a gigantic building was falling down over my head (the guy i loved was inside the building). I turned my head to see him but i didn't see anything. At that moment in the dream i felt pain. Like actual heartbreak, even when i woke up i'm still feeling pain. What does this mean?