I completely agree with MW. I had 4 miscarriages, 3 were confirmed blighted ovum, and now we have 3 healthy children under the age of 4! How far along are you do you think? Just tell/ask your doctor you want an ultrasound at 6 weeks along to see the heartbeat to ease your mind. Hopefully, he will understand.
In the meantime, pray and relax and think on positive things "I will carry this baby to full term and it will be a healthy baby." Just roll that over and over again in your mind and that will help your nerves. You have to fight against negative thoughts and past experience. Believe and trust and wait. :) That is what I have had to do. We are trying for #4 and I still have to work on it!
(BTW: I grew up in Hayward CA! I miss Callie sometimes, especially the food!)