Amniotic sac

I am about six weeks pregnant I just found out a few days ago and today was my first sonogram of the baby at a free pregnancy center. As the technician is looking at my stomach she asks me if I am sure I am pregnant, she kept looking and looking until she finally found a small little looking pea which is my amniotic sac but you can not see a baby in there she told me it was too soon to see the baby and I should consult a specialist. Could there be something wrong with my pregnancy? I am freaking out a little and I have my appointment with the specialist in two days.