172 bpm and earlier GA than thought

So had a bit of a scare today and went to ER. I had my first ultrasound and the heart beat was 172 bpm. Doctor also said baby was measuring only 6 weeks 5 days (1.3 cm CRL) when I thought I was 8 weeks 1 day. But I know things can happen to throw off due date. But 172 seems kind of high though. Anyone else experience this?

Note: I normally would trust a doctors word but they told me at ER that it was measuring 6 weeks 2-3 days but then my online records say 6 weeks 5 days. And they also did not mention they found a small cyst on my right ovary. The whole experience there just felt like they didn’t take me seriously at all because I wasn’t bleeding heavily and cramping. I started to bleed again on the way home and it seems to be coming in gushes rather then steady flow.