Hi ladies! This is my first pregnancy and I’m so confused by my hCG levels and hoping someone can help me out!

Dec 10: First day of my last period

Dec 29-Jan 1: Pretty sure when we conceived

Jan 8: first day of expected period

Jan 10: first test was negative

Jan 12: first positive test

Jan 18: hCG levels 700

Jan 21: hCG levels 2400

So my questions. My app and my doctor say about about 6w3d. But 700 hCG at 6 weeks is pretty low. If we conceived around New Years that would put me at 3 weeks, meaning my test was positive only 1.5 weeks after conceiving.

Also everything says hCG is supposed to double every 48 to 72 hours, but my tests were taken 72 hours apart and jumped from 700 to 2400, which is more than triple.