It's important to remember that the president doesn't make the laws, only signs or vetoes them and we have a bicameral legislative body that hopefully have cooler minds. If that fails we should be able to rely on the Supreme Court to keep us relatively safe. If this doesn't give you any peace of mind I don't know what to tell you except see an MD for your anxiety.
Taking the President-elect at his word when he threatens your well being is not, in fact, a sign of mental illness. Observing that he has filled his transition team with people who threaten your well being is not, in fact, a sign of mental illness.