6 weeks pregnant (conception date). transabdominal ultrasound doesn't show anything. possible etopic? no s/s of ectopic.

Different ultrasound: at 6 week gestation, your developing baby would be no larger than a pencil eraser and could easily be missed on a transabdominal ultrasound which depends on the skill of the of the ultrasonographer. Performing a transvaginal ultrasound would be another option. Waiting and repeating the transabdominal may be a good option as well, and your obstetrician should be able to help guide the choice.