My first ultrasound today with a big surprise!!

Just had my first ultrasound I'm 6 weeks 4 days!! Saw the heart beat and it was amazing, then the Dr said oh it looks like we might have twins! So after my husband had a panic attack the dr said he wants us to go for another scan at the hospital next week to be positive. A few mins later the nurse walked in to take my blood and saw my pictures and said oh ocongratulations TWINS. Has this happened to anyone? I'm gonna freak till next week!