I don't know what country you're from, but in the US at least, bringing those people without informing you or warning you in was probably illegal. I'd complain to the hospital. Depending on how that went, I'd start looking for a lawyer.
One good thing happened in that visit: he didn't tell your mom anything about you. That would have been a violation of doctor/patient confidentiality.
I've had trainees attend my medical care several times. Every time, the doctor has said something like "Hi, these kids are following me around as a part of their residence program. Are you comfortable with them observing this visit?" As far as I know, you should have a say about anybody being there, unless you are evaluated as being a risk to the doctor.