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 breathing difficulty, new or severe chest pain, signs of a serious allergic reaction, or another immediate medical danger.
Do not assume that every intense physical symptom is caused by a phobia.
Seek prompt medical assessment if you faint for the first time, faint without a clear trigger, become injured during a faint, or have physical symptoms that are new or do not follow your usual fear pattern.
Get urgent mental health help if distress leads to thoughts of harming yourself or if you feel unable to stay safe.
A specific phobia is not usually an emergency, but an immediate safety risk is.
Arrange a routine appointment if fear has lasted for several months, is causing significant distress, or is limiting healthcare, work, education, relationships, or travel.
Help is also appropriate if avoidance is growing or if you are using alcohol, sedatives, or other substances to cope.
Every sign above is quoted from the sofidex article on Phobia - simple/specific. If you are not sure, err upward — it is always reasonable to be checked.