Further along?

So I went in for my first ultrasound on the 27th may I should have been 7 weeks 3 days I had an early one because I had a miscarriage and a complicated dnc many years ago. This is my first pregnancy since. I saw the heart beat and was 169 beats but they had a dr. Come in to look and she told me to come back in w couple weeks because the baby looks bigger than what was projects as how far along I should be. But it's still so early it's hard to get an accurate picture to know Or that maybe it's twins sharing the same sac which is not good or conjoined twins. I didn't see anything that looked like 2 baby's and I'm praying it's just one baby that is further along. Has anyone else had a similar expierence and everything be ok? I won't go back until June 16th! I'm currently due Janury 10th if I'm not further along.