It is known as "Catastrophizing" and describes the feelings of someone who thinks the worst will happen. Because it is essentially about exaggeration, many people think that they are "just exaggerating" an experience or event, but it is not so easy.
For example, some people may worry that they will fail an exam. Based on this, they may assume that failing an exam means they are bad students and will never pass, never get a degree or find a job.
This experience is not as simple as "over-exaggeration". It is often not intentional. These people may feel that they have no control over their worries and this affects their health.
It is unclear what exactly causes it. It can be a coping mechanism learned by family or other important people in a person's life. It may be the result of an experience, or it may be related to brain chemistry.
Fortunately, it is a condition treatable through therapy and practices that control or calm thoughts.
Burimet: Psychology Today, Healthline