Yolk sac and fetal pole

Susan

I have irregular periods and am trying to identify how far along i might be. I did a beta hcg on Apr 30th it was 3555 and then on May 2nd it was 7021. However todays scan only showed a sac and nothing else. CAAN I BE TOO EARLY TO SEE ANYTHING ELSE?? I AM FREAKING OUT!! As i have a history of previous miscarriages..

Note: LMP is March 20th