Tell your doctor the full details
Be honest, tell the doctor every symptom and what you did, honestly and openly, so he can make the correct diagnosis for you health.
"took some illicit drugs?" tell them so the police can prosecute you
"suspected HIV from some sleezy sex?" tell him, so he can share it with the health insurance company.
"dizzy spells", be sure you tell your doctor, so he can share it with your employer.
Ahh you say, they would never use it like that, Hancock promised! See the City of London "Ring of Steel"? They promised it was to counter terrorism, now its used for parking enforcement, local driver taxation, taxi license enforcement, even littering.
More than that, it will post-hoc be used for that. In other words, even if it isn't used today for that, the data you told your doctor NOW will in be handed over LATER and used for that purpose.
Recognize the pattern NOW, and watch what you say to your doctor NOW. Can this be used against me at some future date in any employment, insurance, or other context? If the answer is yes, then STFU and don't tell your local snitch, erm local medical practitioner.
This is a no win situation, BMA is weak as hell here, that data will be slurped and probably already is being slurped. It is not a "communications" issue. Recognize it, and protect your own data from your doctor.