Internal scan twins...

Got my internal scan last week I was 6weeks.. she was silent for 10minutes then said were expecting twins she could only see one Sac a time with baby's but they are small one on the left and one to the right. Since that day I'm wondering has she maybe got it wrong as she coz only see one sac at a time? Anyone else had this before?? I'm back next week for another scan but I'm literally scared :(