ultrasound dates! help?

It's been 7 weeks 3 days since my last period and had an early scan today due to a previous ruptured ectopic pregnancy and miscarriage. anyway the Dr told me I need to come back 2 weeks as I'm still only 5-6 weeks. I saw the till sac so I know it's not another ectopic (yay) however I'm really confused?? did I just ovualte late??? sorry for being thick