Probability of Pregnancy?

So I got the implanon in 3 days ago on the 6th day of my cycle. and had unprotected sex the day after... My doctor neglected to explain when it is safe to do so and when it's not (not that that's a valid excuse for my doing something stupid) and only after googling it have I found out that I should have waited 7 days as it only work immediately if you put it in before or on the 5th day of your cycle... I plan on taking a preganance test on the day I expect my period but I was just wondering if those who have been in the same predicament know what the probability of my being pregnant might be?
Updates:
7 d
*pregnancy
Probability of Pregnancy?
0
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