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 you have sudden, severe pelvic pain, especially if it is one-sided or accompanied by fainting, severe weakness, shoulder-tip pain, or difficulty breathing.
This is particularly important if pregnancy is possible.
And for anyone, someone who:
is bleeding heavily and it will not stop with firm pressure
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 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
Heavy bleeding also needs urgent attention if you feel faint, confused, short of breath, or unable to stand safely.
Arrange same-day medical care if pelvic pain occurs with a fever, foul-smelling discharge, repeated vomiting, or rapidly worsening symptoms.
Seek same-day advice for pain or bleeding with a positive pregnancy test or a missed period.
And for anyone, someone who:
has abdominal pain that is severe, constant, or getting worse
3
Does any of this apply?
Book an appointment
Book a routine appointment if:
Pain regularly stops you working, studying, sleeping, or exercising
Symptoms are becoming more severe or lasting longer
Self-care and non-prescription medicines are not helping
Pain occurs between periods, during sex, or when using the toilet
Your periods have become much heavier, irregular, or newly painful
The article also says
New period pain after years of manageable periods should also be assessed, even if it is not urgent.
Every sign above is quoted from the sofidex article on Painful menstrual periods. If you are not sure, err upward — it is always reasonable to be checked.