I've been caled "Doc" for many years now.
Many have been called "doc," but that doesn't make them assume to have any such degree or authority, unless they are puffed up and into status games.
State plainly your license, degree, and medical standing.
Are you in fact a licensed medical physician able to give medical diagnosis and provide medical prescriptions?
Giving medical instructions on what medications are or are not appropriate to a person under a doctor's care places one in liability for the negative outcome should any person that follows the "advice."
If you are even merely a holistic medical resource, there are legal ramifications that are to be followed.
Psychologists and professional counselors (including pastors) are not endowed with the same authority as a psychiatrist, neurologist, and other medical professionals.
It is important that those folks who deal with humankind with no license to prescribe or dispense controlled substances do not assume they have "all knowledge," and that they can "prescribe" by advice or suggestion, or they may fall under rebuke by legal authorities.
Even a poor school teacher cannot recommend a parent take a child to a doctor without putting the school system in liability for all medical care of that child.