Encountering bad turbulence?

When I was flying from Atlanta to Indianapolis....our plane hit major turbulance. All the sudden we dropped and (now I know why we wear seatbelts) my seatbelt caught me but I came completely off the seat. Of course I screamed I thought we were going down, then the plane leveled out (or something) and I was flat on my again, we did this once more and I came out of my seat again we all screamed again but they started laughing...I didnt I was holdin on to the seat with my eyes wide looking around and movin my knee up and down...nervous habit I guess....when we landed I called my brother and was like PLEASE FIND ME IM READY TO LEAVE NOW! I wanted to kiss the ground!! anyone else experienced this kind of a scare?