I had the same problem. I have been having symptoms since we started to try for a baby, and basically fell pregnant straight away. I was getting tummy pains and went to the doctor, who refered me for an early scan.
The scan has shown that I am only 5 weeks.....But I had estimated at least 8 weeks going on the symptoms I was having and how long they have lasted. I am going back next friday to have another scan.
Basically, I understand that I am either not as far along as I thought I was, or the pregnancy go to 5 weeks and won't progress. I am taking the attitude that everything happens for a reason and I this pregnancy is not progressing, then it wasn't right and I will have to try again.
Fingers crossed for us both eh?
Xx