S.M.
Well I did know at 5 days once. I had gone to get on birth control in the 80's. We didn't even have pregnancy tests that were easy to use or cheap. I certainly wasn't thinking yet I was pregnant. But the doctor said I was a little swollen and I was either pregnant or had a cyst. So he did a blood test. Since I had only had sex one day that month and one day the previous month, and I had a regular period, there was no question to the length of the pregnancy. I wasn't "swollen" enough to be a month pregnant. I seriously wonder how in the world I could have been swollen at all! My daughter is 25, almost 26 though so I certainly was.