A.H.
I have 4 kid and 6 pregnancies... I have always just known I was pregnant at around 5 weeks with no symptoms, except for my #4 baby at which it dawned on me I should have had a period 2 weeks ago...surely not... and then a oh yea...wow (I found out I was pregnant with #4 when #3 was 5 months old)
Anyway, some women don't really realize they are even pregnant until they are 2 -3 weeks late and lots don't really have symptoms til more in their 2nd trimester. I learned from all 4 of my kids that measurements from sonograms aren't always on key either.
Stress is really bad for a pregnancy. It can even make your baby stressed out. Don't worry too much. Did you doctor do blood work? That would answer your questions on hormone levels.
Just take each day as it comes. I miscarried at 10 weeks and at 7 weeks...both were hard, but there must have been a reason. I wouldn't tell many people, and as long as you don't have any spotting or anything more than that, try to be excited. Babies tend to grow how they want despite dates and measurements!
I hope everything workds out.. good luck...