Due date pushed back

Emily

I thought I was 8 weeks but I had my first appointment this morning and the midwife said baby is measuring 6 wks 6 days.... uhhh! Anyone else have their due date pushed back? Makes me a little worried, but we saw and heard the heart beat and midwife seemed to think everything was fine. I was breastfeeding my 11 month old at the time of conception which makes midwife believe that the breastfeeding caused me to ovulate later than normal.