It is easy to see why someone would be mad, confused, angry, upset, etc. when bad things happen that are out of our control. What helps, but is hard to do is to have a forgiving heart and put your trust and faith in God and the future. Until you can forgive those who have done things that have affected you and others badly you remain trapped in the current of an inescapable whirlpool.
Model for children what you are having the hardest time managing for yourself. You are their example. While it might be hard, it is easier if your focus is on them rather than on yourself or on the person who has caused the problem and the feelings.