first ultrasound

Sidnea
Today I went for what was suppose to be my dating scan.. according to my LMP I should be 7+1
I got my first positive hpt about 3 weeks ago. 
The sonographer could barely find anything just the gestation sac, even that was hard to find, he said he thinks my dates could be out and to come back in a fortnight. He said he's not worried as I haven't had any pain or bleeding or anything.. 
my periods are super irregular, I was getting them every 12-18 days from being on the mini pill 
but of course I'm worried ahah! I've been hanging out for this scan for so long now I have to wait even longer! Has anyone gone through the same and had healthy bub? Heeellllppp hahaha