Some very good advice there but I think you were asking about how to stop feeling scared about the thoughts of something happening. Yes?

Preparation. Prepare yourself for the worst scenario and share your fears with others, a trusted neighbour perhaps who might be aware of your comings and goings.

Make a plan, like the one most people make if there was a fire and they had to leave their home. What would you do? Who would you call? Who could come to your aid the quickest? Planning this might be a bit scary but once everything is in place you should feel less scared about thoughts of attacks.

And if need be, stop watching the news. I have. lol