What are you thinking about? Your thoughts are determining your perception of reality. Are you testing your thoughts to see if they are even true? What you think influences your emotions. Your emotions influence your beliefs. Your beliefs create behaviors. Your behaviors create your physical reality. This is why thoughts need to be tested to see if they are accurate.
How do you test your thoughts?
First: Is this thought true? How can you know? Prove it true or false.
Second: Who do you become without this thought?
Third: Is this thought rooted in realistic or unrealistic expectations?
Fourth: Can you reframe this thought to make it completely true with realistic expectations?
Fifth: Do you realize that you can only control your beliefs and behaviors, which develops your own character?
Sixth: Does this true thought create growth and maturity?
Seventh: If your thought is not true did you discard it? Go ahead and do that now. No reason to think about things that are not even true.
If you find it difficult to test thoughts, begin with an emotion you are experiencing and go through the process that way. Emotions are messengers created by thoughts. Learn from them.
Most importantly, keep practicing this and be amazed at the dramatic way this impacts how you perceive reality and manage stress.
You can control your own mind.
Have fun!