Confused, please help…

Good day ladies, it would be greatly appreciated if any of you could help ease my confusion and help me better understand what exactly is going on. Sorry for the long text.

According to my calculations, my last period was December 28,2024. It lasted the usual 4 days. Around January 26th I had what I believe to be implantation bleeding. Fast forward to 3 days ago, I found out that I’m pregnant. I had a urine test done at the local clinic that confirmed it. My doctor also had bloodwork done and sent to the lab for quantitative/qualitative testing. The results came back this morning, and they indicate that I’m supposedly only one week pregnant. Is this possible? Shouldn’t I be further along? How can I know how many weeks am I? Can the results be off sometimes? I have so many questions and am so confused and confused. Please help. 🙏🏻