Measuring 2 weeks behind

AC

This is my 2nd pregnancy and according to my last period I should be 9 weeks along. My first prenatal appointment was yesterday and the midwife said the baby is measuring at 7 weeks. She said other than that everything looked good. I am nervous though. Is this something to be concerned about? I'm waiting on my insurance to be able to make an appointment with one of my OBs ultrasound technicians.