Thanks for your query.
First of all i would like to point out that the findings on ultrasound
depends on your gestational age
During the very early weeks,the only thing that might be picked up would be endometrial thickening and then at about 5weeks or so,the gestational sac
becomes the first part of pregnancy
that can be visualized on ultrasound. Fetal poles appear afterwards and then at 6weeks+ the fetal heartbeat is appreciated.
Secondly,one of the markers used in checking for pregnancy is the beta - HCG
, so it quite confusing if your pregnancy test is positive and the labs was not able to pick up HCG levels in your blood.
I suggest you do a repeat ultrasound scan after some weeks and repeat the serum HCG test.
Thanks alot. Wish you well.