You can do early morning jogging for 15 mins daily Along with you can do meditation/yoga/pranayam,whichever suits you You can avoid junk food and take healthy diet Apart from that you can do deep breathing,when you have overthinking You can also do reverse counting like 100,99,98,97... And so on It will make you calm and relax Do some extra curricular activities And spend all your time in doing some activities Do Jacobson relaxation technique https://www.healthline.com/health/what-is-jacobson-relaxation-technique