The world ends without you

This was a two part dream.  

The world was minutes away from an armageddon-level event caused either by nuclear warfare or environmental disasters (I'm not sure which, but it wasn't good).  Everyone had been instructed go head to their nearest shelter and await further instructions.  I was surrounded by people panicking and fleeing in all directions.  I was also acutely aware that I didn't have my fiancee with me as she was several miles away in another town. I also had no way of reaching her.

This part of the dream ended as I headed out into the night looking for the other shelter.  The streets were nearly empty and the sky pitch black.  I saw very few people out on the street and missed my fiancee.  A sad song played in the background with lyrics from a song I wrote years ago. I woke up feeling very melancholy.

When I went back to sleep, the dream continued, but this time, I had my fiancee with me.  We were looking for a shelter together this time and people around us were running around in terror.  I then told my fiancee that I knew we could escape the impending disaster by jumping into a parallel dimension, but to do so, we'd have to go to a park on the top of a hill that was in the opposite direction of the shelter everyone was running to.  This dream ended as we held hands and started to head towards the park.