First scan

So today I went for a reassurance scan as had a miscarriage last year. Going by first day my last period I should be 7w4d. When she dine scan we seen wee heartbeat flickering away but baby only measured 6w6d in one scan picture and 6w4d the second one. She said not to be worried about measurements as baby is that small that it's hard to get an accurate measurement that early but I can't help but worry. Please don't judge me. Just worrying incase the baby not growing properly etc. Has anyone else has this and went on to have a healthy baba

Pictures below of scan she printed out for me