As bad as things can get-- and there are times when they can be absolutely bad-- we still decide how to approach adversity and bad times. It wasn't always bad, and the time will come when it's no longer bad; while we're in a bad time we just have to accept it and keep moving forward. It's bad enough to deal with bad times, we shouldn't make it worse by feeding our minds with negativity or bad thoughts.
Bad thoughts enter the mind and pass through the mind quickly-- we can't avoid that. What we can avoid is dwelling on bad thought longer than necessary. If the bad tought enters the mind, let is pass through as quickly as possible. Let it get flushed out.
Just as incoming bad thoughts take up space in our minds, so do good toughts. We need good thoughts to take up valuable mental real estate so that bad thoughts don't find a home there. The more good thoughts we have-- memories, questions, inquiries, experiences-- the better prepared we will be to handle bad thoughts. If you're not at a level where you can do that, the time to start is now so that you can grow stronger.
One of the reasons Rocky Balboa has been a worldwide phenomenon for 35 years is how he handles bad times and adversity: the brutality of boxing, defeats in the ring, insults, death of those close to him, financial ruin, family disappointment, even government bureaucracy. In the 2006 movie Rocky Balboa, Rocky has words of wisdom for his son based on his hard-fought life and experience:
Let me tell you something you already know. The world ain’t all sunshine and rainbows. It’s a very mean and nasty place and I don’t care how tough you are it will beat you to your knees and keep you there permanently if you let it. You, me, or nobody is gonna hit as hard as life. But it ain’t about how hard ya hit. It’s about how hard you can get hit and keep moving forward. How much you can take and keep moving forward. That’s how winning is done! Now if you know what you’re worth then go out and get what you’re worth. But ya gotta be willing to take the hits, and not pointing fingers saying you ain’t where you wanna be because of him, or her, or anybody! Cowards do that and that ain’t you! You’re better than that!
Source: SucceedFeed.com (emphasis added)
Other people have said similar things, but this is what I go back to.