Shake it off. Easy to say, not so easy to do. But it's key to inner peace, which is key to happiness.
So much is out of our control. So much doesn't make sense. And a lot of injustice and unfairness surrounds us. Accepting that and learning to let go, truly and deeply let go, will help you through the rough times. I speak from experience. Lots and lots of experience. My hard earned letting go skills serve me on a daily basis. And yet there are still times I fail. It's something I find must be worked on constantly and quite consciously.
The mind is very powerful. If you begin to rein in your thoughts when they go dark and negative, and stop them at the door, you'll also stop the rush of negative emotions. I'm not talking about creating a state of denial. But if the thoughts have no purpose other than reinforcing your feelings of being a victim, or of injustice and insanity, then why continue allowing them into your mind? Why entertain these thoughts?
Accept the negative and focus on good thoughts. Your energy will change. Your energy will strengthen you. If something CAN be done about the negative things going on in your life, it will come from being positive and concentrating on what you can control and on things that feed your soul versus things that feed your pain and anger.