I work in the medical industry. Luckily for you, if you tell the school (or who ever) that you had a doctors appointment, there is no way they can verify it. It is against the law to give out patient information to anyone other than the patient (or parent if a minor). If they ask you for a note from the doctor, just say you tried, but couldn't get one. Doctors are so busy they don't have time to write notes to the teacher.
