I had a scan at 7 weeks because I couldn't quite believe I was pregnant. Looking back itseems a bit silly since I had 2 BFPs and no period but there's no accounting for irrationality 8-[ .
The first GP I saw said there was no need so I went to another and she wrote a referral for me.
It really was reassuring to see the little blob so I'm glad i went or I'd probably still be fretting now.