Is it possible to hv delayed conception.

My last period was on 29th July. Since then no periods and I did not worry because past 15 years I am having delayed period issue and being a first stage PCOD patient. Since then I and my husband had sex 3-4 time and the last one was on 22nd Sept. I did a home pregnancy test on 28th Sept and got a very faint line. Reached to doctor and from Beta test she confirmed a 5 week pregnancy with Beta count of 494 only. Later I had done ultrasound on 8th Oct which showed 5week 2 day pregnancy. I continued taking medicine and Hucog 5000 injection. Today (27th Oct) I went for followup and doctor confirm that there is no heartbeat in the fetus. To my amaze the doctor said its only 5 weeks 6 day pregnancy. Three weeks gone and only this much growth. Doctor advised to wait for another 1 week and see if heartbeat comes, else we need to terminate the pregnancy. Please suggest if this could be a case of delayed conception? Attached are reports.