How many weeks pregnant were you when you found out you were pregnant?

I was 4 weeks pregnant when I found out by accident through a blood test. It just so happened that I had a check up which required a blood test, which in turn used hCG, the pregnancy hormone, as a marker. It was an unplanned, but not unwanted surprise. I suspected something because my period was late by a few days, but wasn't very sure. Looking back, it was great that I found out so early as I took care of my body better after finding out I was pregnant and refrained from strenous activities. I still enjoyed my swimming sessions greatly and it helped me keep active during pregnancy.