Very early scans

Aimey

So I had a scan Sunday and nothing could be seen on screen; had another one today and the gestational scan could be seen but nothing more. Hospital said it measures just under 5 weeks but can’t give any dates as it’s still quite small, I believe I’m around the 5 week mark as can’t go of last period as I’ve ovulated late, has anyone else had a very early scan and only seen the sac is it normal for 4 1/2 - 5 weeks??