had my first ultra sound !

Addie
I had my first ultra sound last Monday and I should be about 8 weeks . Since my let appointment. Since my last monthly was August 24th. 
When I went to my appointment I forgot to make sure my bladder was full, and now they're saying I'm only 5 1/2 weeks , they took abou 15-20 minutes to find the baby, and they were telling my my uterus faces different than most woman which makes it harder to get photos early on.. 
Should I be worrying ? Or is it just me