A doctor in a dream typically represents healing paired with authority -- someone, or some part of you, trusted to know what's wrong and how to fix it. Visiting a doctor in a dream can reflect a need to address something you've been putting off, physically or emotionally, while feeling exposed in their presence often points to vulnerability around admitting you need help at all.
You can address Mercury on the empty signs while the Moon can be addressed on both positions indistinctively. - Picatrix (Andalusia, ~1000.AD)