One possibility is that my grandmother used to live on the second story of a small shopping center, and we would go downstairs to buy comic books and candy when we stayed with her- so the idea of 'my house' being connected to a shopping mall speaks to a longing for simpler times, especially since my grandma was the most loving person in my family and I miss her terribly.
Another possible symbolic meaning is that my house represents my being, and I have a public persona, which is reflected in the connection to a public place- a shopping mall.