Ultrasounds are never 100% a sure thing as to the gender.
Some doctors offices now are not allowed to tell the sex because they have been sued for these exact reasons. People not getting what they expected.
The gender is never a sure thing. Your doctor should have told you this.
I wanted to find out what my fiance and i are having, but the nurse said they were unauthorized to say, but because we wanted to know it would be on the results...it never was. I dont think she was allowed to because they were sued before.
You just have to wait and see, and if you get what you were told, great and if not, be happy you have a lovely little life.
Some even say not to start buying things right away because it could be a wrong result.