2 weeks behind in ultrasound

I went to my first appointment last week and I thought I was 7 weeks & 4 days , but during my ultrasound they told me I am 5 weeks & 5 days . But the ultrasound tech said everything looked perfect and there was a heart beat . However I had a misscarige a couple months ago that I was behind in the weeks , but from the start they said it was abnormal , but with this pregnancy they said everything looks normal just early . Should I be worried ? I don’t wanna get my hopes up .