Worried??!?!?

Hi everyone, first time mum here. Few days ago i had light spotting for a couple days it stopped, doctors sent me for an early internal scan.? On my glow tracker i am 7 weeks 1 day, but at the scan it showed up at 6 weeks 3 days and only could see a sac???? Nurse said i could be too early for anything to be picked up on the scan or that the baby is in an awkward place? I go back in 2 weeks time for another scan?? Is this normal?!?