Gender change ?!

Meagan
Ok so I went for an "anatomy ultrasound" at 17w2d, when I got there the tech said she was confused why I was so early that they usually don't do them until 18-20 weeks. Well, after explaining I was upset because I had a reveal party that day she said she would try to find the gender. After a few minutes the baby was wide open and she said she seen the three lines and that the baby is a girl. Well now I have another ultrasound to measure the baby tomorrow and I'm really nervous that she's going to say it's a boy. I'll be happy either way but I did buy a lot of girl stuff has anyone had this happen?!