Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Get emergency help if:
Call your local emergency number or crisis service, or go to the nearest emergency department.
If you are supporting someone in immediate danger, avoid arguing about whether their beliefs are true.
Keep a safe distance, speak calmly, and contact emergency services.
Seek urgent, same-day help if your suspiciousness suddenly becomes much stronger, you begin hearing or seeing things other people do not, or you feel unable to care for yourself.
A rapid change may have another cause that needs prompt assessment, including substance use, medication effects, severe sleep loss, or a physical illness.
Arrange a routine mental health appointment if mistrust or suspicion is repeatedly affecting your relationships, work, sleep, or willingness to receive care.
Support is also appropriate if you are becoming isolated or experiencing depression, anxiety, or harmful substance use.
Every sign above is quoted from the sofidex article on Paranoid personality disorder. If you are not sure, err upward — it is always reasonable to be checked.