Well, it would be hard to say for sure. I think that if you did conceive that it would have been on the 2nd. Just because, we are fertile about 13-15 days after the 1st day of our period.
Now, the fact that you just stopped birth control could play into the scenario. Sometimes it takes a good 3 months to get pregnant.
But, I have heard stories telling otherwise.
I am assuming you are trying to get pregnant?