Return from Earth Dream

I had the weirdest dream.
I was walking up to an old castle that I termed "the invisible fortress". When I entered it, I found it mostly abandoned, I walked through it's labyrinthine interior, passing through doors and corridors. I came across a staircase and walked on, upwards and upwards. I eventually came to what looked like a private room, went in there, sat down, and rested. I eventually heard several loud knocks on the door. I shouted "enter", but no-one entered through the door. Instead someone, or rather something, "entered", from the other side of the room; passing through a door in the wall that was not there before. "She" had a somewhat feminine and humanoid body, but with her body covered in black and brownish patterns. She looked at me and made a sound like an alien high pitched scream. Countless of others that looked like her passed through the wall. They began pulling at me, dragging me across the floor, clawing at me, tearing me apart. They turned into worm-like things, passing through my skin.
Everything turned black. When I regained consciousness, I found myself at the bottom of a tower-shaped building, with no floors or doors, but with an opening towards the sky; I was in a raging fire of black flames. Looking at the sky I saw a glowing white light; somehow it evoked a description of the holy grail I read in a book about the legend of king Arthur once.
I fell through the floor, into the ground, and then into darkness.
I found myself in the middle of a dark void; absolutely nothingness. Yet it felt like an enclosed, walled darkness. I could sense barriers of the void in the distance above me, and around me.
Suddenly a white and glowing humanoid being walked to me; it looked scary, but also somewhat sacred. It extended its arm to me and held a key in its hand, offering it to me.
I decided to take the key.
The being disappeared. Instead a door was visible suddenly. While the door stood in the middle of the dark nothingness, I could see light coming through the cracks.
I walked to the door and opened it with the key.
When I walked through, I first thought I was in my hometown again. The place looked somewhat like an air port, or the outside of a large train hub.
But then I realized the buildings looked far more futuristic, and that I was on another planet. A man approached me and took me into what remotely looked like a futuristic office.
He talked to me and said: "Ah, there you are! It seems you have finally returned from Earth. You spent an unusually long time on that planet".
I replied that I had not really "returned from earth".
He said: "Oh, in that case, don't worry. It's not problem. I will quickly evacuate you from earth".
I wanted to shout that he should not do it; that I would not want to be "evacuated"; but he had already reached for a button next to his desk. He pushed it.
Then I woke up.