i agree with what the others said, probably a fear of losing important things in your life or possibly losing connection to your past (childhood home)
context also matters as well...for example if one's childhood home was the location of horrific abuse, dreaming of it being destroyed might represent a "moving forward" of some sort...however i'm just thinking out loud and i know you said the dreams made you very sad
i sometimes dream of being in my car, going to park somewhere, and i cant get the car to come to a complete stop, like the brakes dont entirely work and my car just keeps rolling slowly, never stopping....and i understand that, to me, this represents how my life is always moving, always busy, never entirely stopping although it may slow down...the dream isn't a nightmare, just a frustration that my car brakes arent working properly in the dream, perhaps a call to myself to "put on the brakes" or "take a break" from my busy schedule
|