Wrong gender???

Alyssa
My husband and I went for a private ultrasound this weekend. I was 14w6d on the day of the scan. The tech said "it looks like it's a baby girl!" - but I honestly have felt so sure and been so convinced it was a boy for my whole pregnancy that I was so shocked to hear it's a girl. We are ecstatic either way and this isn't about wanting one over the other. But I'm just so surprised that I was SO wrong! 
Unless I was too early and she was wrong? Has anyone experienced being told the wrong gender at an early scan like this??