Children in this group were more likely to experience mood swings, trouble in concentrating, and also had rashes. With long COVID, many kids struggle to keep up with their schoolwork or sports. Signs and symptoms of mood swings experienced by kids, and even adults, include suddenly getting angry, sad, frustrated, and getting panicky and worrying too often. Mood swings also include feelings of hopelessness, low self-esteem and tiredness all the time.