abnormal sac

Long story short. I miscarriages on the 1st August, had dc. I got my period back on the 31st August. Ovulated 21st September & got a positive pregnancy test on 1st October! - that puts me at 6 weeks two days if you go off period date... but really only about 3 weeks as I ovulated late... my HCG is above 3000 & is doing as should. However my scan indicated 7 weeks 1 day. - which I know isn’t right. There was no heart beat & the sac was abnormal. (Crinkled) they called it.

However - the sac would be okay if my dates are right. But if there not right it’s all over again! They are watching my HCG levels. And there doing as should but my bloods don’t match my scan.../ there was a fetal pole. Any advice !!!!