My last period was on 2/6/15 on 3/10/15 i took a hpt and it was Bfp. Scheduled an appointment with obgyn who did an ordinary ultrasound and saw nothing then again a transvaginal ultrasound and said he saw the tiniest dot (supposed to be the sac). He asked me to go back on 3/16 to have another ultrasound. Should i be worried? Is it too early to see the sac? Im very worried we've been trying since a year and really want our 1st baby. Please advise