My LMP was 12/29 and according to my dates I am about 7 1/2 weeks pregnant. However because this is my second child I have been cramping so when I went in to see my OB he did a transvaginal US to confirm viability and said that he does see the gest sac and yolk sac but because it is measuring 5.5 weeks he does not expect to see the heartbeat which he did not see. He explained about conceiving before/after period but I am very confused. I am going back in one week which according to him I will be 7 weeks and he said that the heartbeat should show and if it does not then it is a miscarriage. I need assistance and am very scared.

Maybe I am not understanding you. This post was very clear, you seem to understand what the doctor is saying. Can you please give a question as to what exactly you are asking and I will try to help further.

I understand your fear, you are in what seems to be a tough situation. I hope all works out for you.