Odd dating question

Kim

So I had 2 early losses , so I was obviously tracking like a fool... pos OK tues June 13, and temp dip we DTD ( only other time was 3 days before) cramping Wednesday all day and temp spike Thursday ... pretty well confirmed O (plus I always O CD 16/17 and this was CD17) well first ultrasound was 5w6d measuring 6w1d second was 7w6d measuring 8w1d they moved my due date from 3/6 to 3/4 even though o was pretty well watched and lmp suggests due date 3/6.... could my bean just be a little big (which I def prefer over small) ... I really doubt I ovulated 2 days earlier with all signs lining up appropriately