Your doctor is there to provide for your health and well being. His job is to keep you healthy, that is their main concern. I doubt very much that, barring your need for any serious medical treatment, that they would find it necessary to reveal your sexual activity.

You can call the doctor's office, I don't know what state you are from, and just ask the question without revealing your identity. Or you could tell them you are scheduled for an examination and are worried about this matter. See what they say.

You could also ask to speak to the doctor in private, of course you would have to reveal your name but, the office people are not interested in telling your mother about this. You are entitled to ask questions, give it a try.