What Causes Severe Backache And Slurred Speech After A Back Injury?

I'm a 17 year old girl and this morning I slipped on the last three stairs in my house and hit my lower back pretty hard. I got so scared because for about a minute or two as my grandparents tried to help me up and ask what was hurting, I couldn't form the words to come out of my mouth as anything other than sounds. It was like I could think what I wanted to say but not speak. The sounds were similar to those of a person who is mentally incapable of speaking. I also couldn't move myself from the position that I was in. When my grandparents reached to grab my hand I couldn't get my arm t move toward them. Now I am able to speak and walk although my back hurts really bad. What happened? Did I damage my nerves? And what should I do?