6 week scan but no fetal pole


I thought i was 6 weeks + 3 days and today i went for a scan.

They said the sac was 5mm and is in the correct place, but no fetal pole could be seen. They also said they think im 5-6weeks.

I had extremely sore boobs and sickness untill 2 days ago when it all suddenly disappeared.

I have another scan booked in for next week. Has anyone else experienced similar?