The most fertile days of the cycle are 2 days before and after ovulation. Ovulation usually happens about 14 days before the next period comes. If your last period started on the 10th of August and your cycle usually lasts 28 days then your ovulation date probably happened around the 24th of August. It appears that the most fertile days for this cycle were 22-26th of August, and not the 14th of August.

Chances for conception only 4 days after your period started (10th August) are very small, almost none.