Boyfriend died in my dream

I had a dream last night about my boyfriend who was lying backside down next to me on the floor. We were watching tv with his family. I noticed he was sleeping for a long time and when I went to go wake him up, he didn't respond. He wasn't breathing and had passed away in his sleep. I was shocked and had no emotions. A few days later, I couldnt hold it in any longer and I just started freaking out, crying uncontrollably. His sister came to console me. The last thing i remmeber was really wanting to speak to him one last time. I woke up relieved that it was only a dream and extremely sad. Why did I have this dream?