I often think about the people who went through the concentration camps run by the Nazis, and many of the other horrific things that Jewish people have been subjected to throughout the ages. I understand that for whatever reason, these things needed to happen, and Hashem must have only been doing it for some reason that was ultimately good. However, it makes me think that many of these people were far greater than me and if it could happen to them, it could happen to me, and that makes me scared. On an intellectual level, I feel like I should say "if that is what Hashem wants of me, I need to accept that", but at an emotional level, I feel scared that it is possible that one day I (and/or my family) might need to deal with something incredibly unpleasant and as a mere human I don't want that.
For clarification, this isn't a question about why do things happen like this. It is a question about how do we cope with the idea that it could happen to us? Specifically, I'm looking for sources that cover this specific topic.