Changed my due date

I had my first appointment yesterday at what I thought was 10w6d, but after she measured my uterus, she said I was too small to be that far. I had an ultrasound today to verify the date, and little peanut is only 8w5d. It's hard to wrap my head around when I think about my last period and because I have a decent idea of when he or she was conceived. Curious if anyone else's due date was changed? Thankful our little one is healthy, and I'm so glad we got to see him or her, but the end of my first trimester being even farther away is a sickening thought, haha. The nausea is only getting worse with time.