First appointment advice

We went to our first appointment today I though I was about 8 weeks pregnant based on my last period we found out we were pregnant on Christmas eve which was a month ago. And I noticed the baby looked small. My dr measured and we are only 6w4d! We heard and saw the heart beat he said it was about 120. I’m so nervous now that something could be wrong. Did anyone else have this happen? I was taking opk and pregnancy tests right after so I guess if anyone would find out early it was us but my last period was 11/24 and I’ve always had long cycles except last month I had a 32 day cycle for the first time in my life usually it’s like 36-40. I’ll go back in 2 weeks on the 6 for a 9week appointment and I’ll be 9 weeks 2 days. So really just praying and hoping our baby is healthy and growing. 😭💗 first baby so I’d love all the experience and advice in the comments you can give