7 Weeks 1 Day?

I’ve been horribly sick so I seen my OB yesterday, I have a scheduled first ultrasound for October 29th but since I was in she wanted to check on everything and said we’d still keep the other appointment as well. during the ultrasound she said I’m measuring about 5 weeks instead, it doesn’t make sense because I know the dates from my last menstrual (thanks to Glo❤️) she said they would measure the baby on the 29th but that looking at it, it looks to be only 5 weeks along. Which would mean I found out I was pregnant at 2 & 1/2 weeks pregnant?? I’m just wondering if anybody have ultrasounds from 5 or 7 weeks. Does this look similar? I’m a little worried about it measuring two weeks behind. Please share your experience ❤️