What does this dream mean?

Me and my dad was in a car, he was driving. We were driving on a bridge, up a hill. I could see the ocean under us. Suddenly everything in the car stopped working, the brake, the steering wheel, my dad could not do anything. Then the car just starts speeding, and shoots straight into the sky. Everything is shaking and you can just feel the car going really fast, like a spaceship, into the sky. I was clinging to my chair, trying to figure out what the hell i was going to do when it fell into the ocean (i'm very afraid of deep water), and i felt like i knew what i was going to die. I was just waiting for us to crash into the water..i've never been so scared. Then suddenly i wake up, and i'm laying in a really awkward position with my head on my laptop (i have it on a chair next to my bed) and just as i wake up i can still hear that loud noise of the car, it feels like my head is vibrating, so i panic and sit up.. and realize i was dreaming. I was literally so scared i was shaking and i started crying, then went back to sleep. What could this mean? I don't understand it at all. Please help?