Blighted Ovum

Hey ladies, so I just got back from the dr and for the 2nd time there was no sign of a baby. Little back story, I have PCOS so I don’t have a regular cycle to base how far along I am. I am Measuring at 6+4. According to my HCG draws and when I think I ovulated according to the test strips, I should be about 7+3. I’m waiting on my labs to come back and see what my HCG Is. I go back next Thursday for another US and to decide what the next step is. Has anyone ever been in this position or thought they had a Belighted Ovum and it turned out different?