Remove them from your life. If there is no negative energy near you, there is no negativity.
Beginning signs would be memory loss, inability to do challenges, difficulty completing tasks, confusion with time, misplacing things, poor judgment, etc
Not so much think PE class is just another class and I use it as a study just like hang with my boys and play basketball for a hour I make my brain get loose and not think about anything
Your grades should not be impacted at all just stay on task in your real classes though
IT TAKES 2 WHOLE MINUTES TO WASH YOUR HAND PROPERLY OKAYY HEALTH !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!