Hi, I am 31 years old and pregnant I am

Patient: Hi, I am 31 years old and pregnant. I am concerned about the growth of my gestational sac.I had an us on May 13 showing only gestational sac (4.45 x 7.61 mm).Then I had another us on May 19 (6 days later) showing gestational sac (11.2 mm) and yolk sac (4.4 mm).I know for sure by sticks that I ovulated on April 20. I had an only intercourse on April 14. So it was pretty strange for me that I got pregnant, anyway I was happy with that.Now I am worried because doctor says that if we don’t see the embryo on next us it is probably a blighted ovum. Besides, I read on the web that the gestational sac is supposed to grow 1mm per day and mine is growing much slower. What do you think of my situation? What are the odds? As you can imagine, it is very hard to go through this waiting days.Thank you very much for your help and advice.Best regards