Confused

So I found out I was pregnant again (8 months postpartum) & according to my lmc I should be 5 weeks & 6 days. My doctor did a ultrasound (history of miscarriage & other issues) & I’m measuring 4 weeks & 6 days but she told me the ultrasound is giving conflicting measurements & it appeared there were 2 sacs.

(This was with an abdominal ultrasound) so she did a transvaginal & saw NOTHING! But my test was positive.

I have to go back in 2 weeks I’m just confused to what is going on. Anyone have any ideas?