Engaging in a sport that requires you to focus on your body and/or eye-hand coordination is a good way to clear your head.  Plus, exercise brings the added benefit of producing the brain's feel-good neurotransmitters, endorphins, which will improve your mood. Challenge yourself mentally by completing a Sudoku or crossword puzzle, solving complicated math problems or following a complex set of instructions to complete a project.  The mental focus it will take to do these kinds of activities will leave you with no time or mental energy to think your unwanted thoughts. Laughter can take your mind off worries.  When we laugh, our brain is engaged--it's instructing our body to make a series of gestures and sound.  Laughing helps reduce stress, so if your recurring thoughts are causing you anxiety, laughter really is good medicine.  Hang out with friends who simply crack you up, rent a funny movie or try a laughter yoga class.  You can even find therapists who specialize in "laughter therapy," which teaches people how to openly laugh at things that aren't usually funny and to use humor to cope with difficult situations. Often the best way to get a thought out of your head is to share it with someone else.  Turn to a friend or family member who's a good listener and tell them what's on your mind.  If you feel as though your difficulty in dealing with your unwanted thoughts is more than a friend can help with, turn to a professional therapist or counselor who can work with you.

TL;DR in Indonesian:
Jaga diri tetap beraktivitas. Lakukan sesuatu yang menguras pikiran. Tertawa. Bicarakanlah.