Is there a term like PTSD for an event you haven’t experienced yet?

Anticipatory anxiety

Anticipatory anxiety is the fear and dread you experience before the event. It’s what’s at play when you spend weeks dreading the results of medical appointment...

Anxiety Canada

Anticipatory anxiety refers to a persistent and often disabling fear of another panic attack. More specifically, the anticipated, though unlikely somatic (heart attack), psychological (loss of control, madness), and/or social (embarrassment, humiliation) consequences of panic attacks are the focus of this fear.

Panic-related behavioral changes include avoidance of activities or situations that may precipitate a panic attack (e.g., exercising or crowded places). If this avoidance pertains to agoraphobic situations and becomes prominent and disabling, a diagnosis of agoraphobia may also be considered.

Science Direct

Like PTSD , Anticipatory Anxiety may be disabling, but can be treated.

See...Anticipatory Anxiety: The Suffering and Solutions in Psychology Today