Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for severe or sudden abdominal pain, fainting, confusion, difficulty breathing, or heavy bleeding.
If pregnancy is possible, severe pain, faintness, or shoulder-tip pain also needs emergency assessment.
Seek prompt testing if you may have been exposed to a sexually transmitted infection.
Avoid sexual contact, or use condoms, until you have received advice and any recommended testing.
Seek same-day medical care if discharge occurs with:
These symptoms can sometimes occur with pelvic inflammatory disease, which is an infection involving the womb, fallopian tubes, or nearby tissues.
Arrange a routine appointment if the discharge is new or keeps returning, or if it has an unusual smell, colour, or texture.
You should also book an appointment for itching, soreness, pain during sex, burning when urinating, or bleeding between periods or after sex.
Every sign above is quoted from the sofidex article on Vaginal discharge. If you are not sure, err upward — it is always reasonable to be checked.