Why does my head physically feel empty in the back?

Sometimes I notice it usually I forgot its even there. But also I think might be related: I may have had a brain injury, I forget what I am doing, where and who I am and feel really uncomfortable and unstable mentally. After it I got dislocated disks in my spine and back. I become anxious. My body begins to feel like light like air and like the world is unreal but not like I'm loosing it. I begin to wonder if the world is real. I don't like the way I feel. If I am in a place with a lot of the same pastel colours everywhere (I did when I was really small) it makes me anxious I begin to believe I have a bird spirit guide teaching me and it makes me think I want to die.