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
Call emergency services if fatigue occurs with:
Chest pain or severe difficulty breathing
Fainting, new confusion, or difficulty waking
New weakness or numbness on one side
Thoughts of suicide or immediate danger from self-harm
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
Seek same-day medical care for sudden severe fatigue with a high fever, repeated vomiting, inability to keep fluids down, black or bloody stools, vomiting blood, or unusually heavy bleeding.
Also seek prompt care if you have severe dizziness, very little urine, or a rapidly worsening illness.
Arrange an appointment sooner if it comes with unexplained weight loss, persistent fever, night sweats, swollen glands, shortness of breath, unusual thirst or urination, or a major change in mood.
3
Does any of this apply?
Book an appointment
Book a routine appointment if fatigue lasts several weeks, keeps returning, is getting worse, or limits work, school, exercise, or self-care.
And for anyone, someone who:
is more tired or breathless than usual doing things they used to manage
Every sign above is quoted from the sofidex article on Fatigue. If you are not sure, err upward — it is always reasonable to be checked.