HI, I Fell Down The Stairs And I'm Not Sure

HI, I fell down the stairs and i'm not sure if I hit my head, but I know that I hit my back. After the fact, when I tried to get up, I passed out. My family apparently moved me to the couch and I woke up there not remembering it at all. I went to bed that night and I woke that morning feeling nauseous, and light headed. Now all day I have felt nauseous and light headed with a slight headache.