Might not be as far long

I had a miscarriage last September and after all my bleeding I did have a normal period October 21-26th . So when I found out I was pregnant that’s when I told the doctors that was my last period and it put me at 13 weeks. I had my appointment yesterday and they used the Doppler on my belly and couldn’t hear anything and the ultrasound on my belly and nothing .... they think I’m not as far long as I may think I am . Even if my last period was in October my miscarriage could’ve compromised my ovulation and so now I have to get a vaginal ultrasound at the hospital .

I’m just a bit bummed because I had finally hit a “safe zone” in my head . I lost my previous baby at 6 weeks .