Confused on dating scan

Alison

So. According to LMP I’m 8 weeks and 1 day. It was on May 28th. Had peak on ovulation strip on 06/13. Took a pregnancy test on 06/23 and it was positive. A reeaaallyyy faint line. That was technically about 9dpo according to ovulation test. But I went to my scan today for 8 weeks and only measuring 7&3. Is baby just measuring small? Heartbeat is fast ❤️