Just now, my eyesight turned blank, completely dark. When I tried to leave the room I hit walls and after a while my eyesight came back with a ringing in my ears. What just happened, is this normal?

i lost my sense of smell this morning i almost cried.

Head rush maybe? Did you get up too fast?

I got that when I got up too fast one morning. I stood up and all of a sudden I was all dizzy and couldn't see anything for a couple of seconds. I ended up stumbling and falling on the floor.

But I was okay after a little bit.

you probably stood up too fast; didn't give your blood enough time to reach your head..take it slow next time..!

Not enough oxygen to the brain. Sit down and breathe

I once woke up because I thought someone was knocking on my door. When I tried to answer it my legs kept giving out on me, like my knees wouldn't work, and my vision kept blacking out and coming back it .I finally scrambled to my door (I dunno, but it felt imperative to answer the door) and when I opened it there was no one on the other side.

Scary O.O