Nothing good ever comes from getting riled up or worried, so just keep calm and you’ll be alright. Meditation is a very nice and calming practice to get into especially through high school so check out some of these apps and accounts to slow your mind and rest your thoughts:

Smiling minds

Calm 

Goodful (playlist on Youtube)

Also, check out this video to learn more about the practice of meditating: 

Video by: asapScience