What is meditation and mindfulness? It's looking for truth. It's seeing things as they are. It's not always pleasant. It's recognizing what something really is; not what you are told that it is. It is your truth, your discovery, your thought.
If you are told something, read something, hear something, experience something, you should not believe it or not believe it. It is only part of the journey to see things as they are. Information should be followed by reflection, not reaction. Of course, one must react immediately in many situations. If rocks are tumbling down a hill and you are in the path, yes, react and get out of the way or you will be crushed. If information comes your way, good or bad, stop to think about the true meaning of that information. Is it too good to be true? Is it too bad to face? Is it true for someone else but not for you? Or just the opposite?
Immediate reaction that would have worked out better with reflection can be reconsidered after reflecting after the fact. Perhaps an apology? Or a change in the course of your actions? Once you find the truth, you will know what you should do.
Some events cannot be changed. The forces of nature are strong and most are beyond our control. The limitations of being human (does anyone live forever?) is the way things are. Mindfulness if still powerful. It allows you to see the truth, your truth. Ah, so mindfulness is a state of depression? No, it is not! When you achieve mindfulness, you will have a power that you never had before. You will see clearer than ever before.
Ah, but why should you, dear reader, believe any of this? You should and you should not. You must discover the truth for yourself.
Be calm, be zen. Peace.