What if I had sex on October 7th 2006 is that when I became pregnant?

You become pregnant by having sex, so it had to happen one of the times you had sex.

If that's the only date you had sex, then I would say yes. If you had sex on other dates, you could have become pregnant any of those dates.

Didi

What was the first day of your last period?

As grammadidi says if you onlyu had sex on that date then yes, but if you had sex on other dates it could be any of those times, since your last period.

Sex = pregnancy.

So anytime you have sex you are risking pregnancy. If Oct 7 was the only time you had sex, then yes that is when you got pregnant.

What did your doctor tell you? S/he will have a more accurate date for you by getting your history and doing a physical exam.