J.S.
If you were that early, I think the only thing the doctor can really test would be your hcg levels (pregnancy hormone) and if those levels are too low to detect or are at normal levels then they wouldn't be able to tell for certain. Sometimes the physical symptoms are more important than the hormone levels and testing they could do anyway.
I had a pregnancy loss at about 4 months along and while we knew I was pregnant and going through a horrible miscarriage I never once had a positive pregnancy test. Not for 4 months. I had every single symptoms of pregnancy except the rising hcg (which was probably why I lost the pregnancy or a sign that the pregnancy wasn't viable).
If your friend was farther along, then that could be why they were able to run some tests, especially if at one point she had positive pregnancy tests.