18 week ultrasound showed wrong gender

Rebecca

We had an ultrasound at 18 weeks with very clear girl parts. Textbook 3 lines (picture shown). Had our official anatomy scan today at 21 weeks and there are VERY obvious boy parts. Anyone had this happen? I'm trying not to be upset because baby is healthy but we were so excited to have a girl after two boys and have already been gifted girl things. Just feeling disappointed 😞