We are provided with negative information all the time by media, it's news (how often do they tell about something nice that has happened?), There are new discoveries of things we can or will definitely get sick of, on social media we often read about how sick others are, we are asked to buy a lot of things that help us to stay above the water surface ...
Be observant on your thoughts. When you are in silence you can practice observing your thoughts. At the moment you think of a negative thought, you say stop! Note and acknowledge that a negative thought appeared and then shut it down. You do not argue, you do not analyze, you do not defend yourself against it, you just stop it.
We have 7 chakras and they are small energy wheels. They have colors like the rainbow and various functions to regulate our mind. If chakras are balanced, we feel good, if they are overactive or underactive, we do not feel good and it turns out in various feelings and behaviors.