I think it's natural to feel this way.

I feel like this often too, especially if I am out on my own. Sometimes, I tend to avoid reading or watching the news because of all the bad things I would see (However, I know it's also good to be aware of what's going on, especially in local areas).

We have to accept that we live in a beautiful world filled with some bad people. Always take safety precautions, avoid certain areas and prevent certain situations (such as walking alone at night in isolated places, unknown drinks, etc) and I think the best thing to do is just try to be alert and aware of your surroundings.