I had unprotected sex on 23aug and got a positive pregnancy test onaug31 do u think that's the day i got pregnant or i got pregnant at an earlier date ?

It Happened earlier: It is highly unlikely that the home pregnancy test is able to pick-up the pregnancy after 1 wk (sex on 8/23, fertilization maybe 8/24-25?, by 8/31 is barely a wk. So i would not pin this pregnancy on the 8/23 adventure. I believe that you may have conceived before 8/15--which is 2 wks before the +test. Consult doc for eval/prenatal vitamins. Congrats on the pregnancy. Good luck.

Pregnancy: Probably earlier, usually pregnancy would positive 10-12 days after conception but since this is close to 10 days i would not say it is impossible.