6 weeks scan, sac growing but cant see fetus

Is your sac seen really tiny? Mine is (but am w6d1 today), so doc can't see yolk sac/fetal pole yet! Only 0.4cm gestational sac (or in obgyn's words "water bag") seen for me on the transabdominal ultrasound. Think transvaginal ultrasounds can see the fetus much more clearly in the first 4-8 weeks! Had my first scan on Sat, going in in 2 Saturdays. Hope you have a follow-up soon :)