If it makes you feel any better the Dash does not really handle turbulence very well. She's built like a brickSh!t house but that doesn't mean she can absorb the bumbs. The wings are quite ridgid thus do not really absorb the turbulence as well as a larger, transport, swept wing aircraft.
It is still nothing to worry about, you just had an unlucky experience. It should get easier with time and the more flying you do.
I guess the bottom line is that deep-rooted regard for self preservation is embedded in our brains and when we experience something to what we may think as threatening our reaction is to avoid repeating the same situation.
Having said that, I don't quite understand what I still doing in Africa now!
