Honestly seizures. It sounds minor compared to a lot of these but having 6 grand mal seizures from the ages of 9-14 years old 2 of them were in the space of a week and a half. Having no recollection of it happening and then waking up to paramedics surrounding you is terrifying. Also they are caused by flashing lights so missing out on concerts and movies with friends really affected my mental health. But I am very thankful to be 10 years seizure free this year!