HELP ME OUT

Jade
I just went for a 6 week scan today I thought I was about 5/6 week pregnant but when I went for the scan we couldn't really see anything but the woman say that something looked like the start of something coming and says she thinks I'm only 3/4 week pregnant has anyone ever had this and went back again on a few week time and everything has been ok please help I'm going insane thinking everything