I have to admit that i go through this from time to time. sydney's death was a prime example, it made me not want to ride on the road. There have been other times as well. But I keep riding. Usually I don't think about it and basically I know that riding is a pretty safe activity.
One thing you might ask yourself is why you never think twice when you hear about someone being KILLED in a car wreck every day, yet who ever stops to consider why we don't give pause? We are so used to people being killed that we simply don't even think about it unless it is someone you are close to.
Even then everyone drives to the funeral without much concern. I think it is that cycling is not mainstream and so it is easy to view it as more dangerous than other activities that the general population participates in.