So my parents wants to know if I'm still a virgin, and the doctor said I'm not a virgin -but I know I have never had sex with anyone. What should I do?

Why did your doc say that? Did he check or something? 

Tell your parents you are a virgin, and if the doctor says you're not, ask him in front of your parents ''What? Did you rape me in an appointment or in my sleep? Because I'm pretty sure I've never had sex, if i did why would I lie? And this isnt your business!''

As far as i know the dr does not have permission to tell any of your personal information (even being a minor) just be honest with your parents.

Did the doctor examine you?  If you've used a tampon then physically you're not a virgin but for all intents and purposes you are a virgin.  You need to talk to your doctor and ask him why he disclosed his patient's information to another party whether that's a parent doesn't make any difference his obligation is to you and to keep your records confidential.

Well .. A doctor's examination can determine if the hymen is still in tact .. But it can not determine if a patient is a virgin...PERIOD. 

The hymen can be compromised by the use of anything inserted into the vagina .... Like a tampon (for example).