My last period was 3/18 that lasted until 3/24. I got a positive pregnancy test on 4/16 and got HCG levels checked and was at a 12 that day! I went to the Dr on 5/4 assuming according to last cycle i was 6 wks 5 days. they did a ultrasound and at that time all was seen was a yolk sac? All she said was I'm extremely early. I have no clue when I ovulated but after adding everything up...nothing adds up at all. I should have seen something more than a sac..right? Please help me ladies.

Thanks!