How do you know?

When you think about it, most of us go through life not thinking about the unpleasant things that might happen to us. We are hard wired for survival. We mostly don't lie awake (without good cause) worrying about aneurysms, strokes, Parkinson's, plane crashes (unless flying out tomorrow!). Cancer breaks that system. We now know that something unpleasant can happen to us. We can't go back to that original state, but we can avoid imagining everything possible as the only alternative. When in doubt, seek qualified advice. As Marg says, time will help allay the fears and sharpen your instincts. We can all spend time worrying about things that may never happen, instead of enjoying as much as we can right now.