6weeks +5 no baby just a empty sac

Has this happened to anybody else I’m really worried as I have M/c 2 years ago and now today I went for a scan as I had spotting and pain in lower left side and they can’t see a baby just a amniotic sac and a yok sac ? I’m sure your meant to see something by now they’ve said they’ll will scan me in 2 weeks to see if the baby has developed and I’m just not as far gone along I’ve had positive tests since a week before my missed period can anyone help I’m just so anxious