FTM (first time mom) here so any help would be greatly appreciated. We went for our us today and it caused more confusion lol! First by my calculations (we used calendar and temp and ovulation tests so we are sure when I ovulated) I should be 9 wks 1 day. Docs measurements put me at 8 weeks 2 days, is this something I should be concerned about? Second, the first time we heard heart rate was 141 BPM and that was 2 wks ago, today it was 184! Concern? And lastly when I was going thru my pics and video today I noticed another dark area behind the sac. Do you think this could be a hidden twin? 4 more weeks til next us ahhhh!!!! Thanks ladies :)