Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek emergency help if:
A sleep episode or sudden weakness causes a crash or serious injury
Someone remains unresponsive or has trouble breathing
An episode includes prolonged confusion, repeated jerking, or blue lips
There are possible stroke symptoms, such as new one-sided weakness or speech difficulty
You feel at immediate risk of harming yourself
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Do not wait for a routine appointment if sleepiness is making driving or hazardous work unsafe.
Stop the activity and seek prompt advice about safety and symptom control.
These features are not typical uncomplicated narcolepsy and need urgent assessment.
3
Does any of this apply?
Book an appointment
Arrange a routine medical appointment if you repeatedly struggle to stay awake during the day despite enough time for sleep.
Also seek assessment for emotion-triggered muscle weakness, frequent sleep paralysis, vivid experiences around sleep, or unexplained lapses in awareness.
New loud snoring or pauses in breathing also need routine assessment.
The article also says
Contact your sleep clinic or usual clinician if established symptoms become harder to control, cataplexy starts or changes, or treatment causes troublesome side effects.
Every sign above is quoted from the sofidex article on Narcoleptic syndrome. If you are not sure, err upward — it is always reasonable to be checked.