I'm the kind of person that gets affected by the weather, a gloomy day can easily fill my head with hundreds of negative thoughts. I actually feel physically sick if the sun doesn't come up for more than two days in a row.
For the past few days, Hurghada fell a victim to a huge cloud covering the entire southern areas of Egypt. That's the kind of weather that makes me feel depressed and gives me minor anxiety attacks for no reason.
I remember in my teenage years I used to think a lot; and I once told my father that I can't control it, I want to stop thinking but I'm unable to. He told me that I'll learn how to control my thoughts when I grow up, back then I never believed this would be possible but now I know I can.
Some things just need time, and learning how to control your thoughts is one of these things. Now I can easily decide to stop thinking about something and remove it completely from my mind; however it's not possible to keep my head blank, so I need to fill the void.
Some people fill it with Netflix or video games, but I get bored of this so fast. The only thing I found working was doing physical activities, that clears my mind of any thoughts.
Try to find what helps you clear your mind and do it, wasting time is not a bad thing. A mind that's clear from time to time is a healthy mind.