Is is possible to see a tiny yolk sack at +/- day 10 of cycle, but have a negative blood test? doc saw black dot and thick lining on transvaginal u/s

U/s in early preg: I will not guess whether you are preggo or not. I can say as a fellowship trained body radiologist of 30 years, that a small amount of intrauterine fluid and decidual reaction is not proof of viable pregnancy. Also, a neg. blood test does not exclude an early preg. A gestational sac would be seen before a yolk sac: http://www.jultrasoundmed.org/content/31/1/87.fu Consider F/U U/S in a few weeks.