Unprotected , chances of pregnancy?

I had unplanned, unexpected and unprotected with a date 8 days ago (8/2). My period *should* have shown up around the 6th/7th-ish. There was absolutely no form of birth control and he did *** inside of me at least once, possibly twice (he was down and out, but then back up and in again lol) - it was absolutely a stupid move on both our parts and believe me, I know it! I'm giving a little credit to the stars, the wine and the cute boy though :). My last period started 7/6ish (somewhere shortly after July 4th) and lasts for about 3 days, I'm pretty sure I ovulated two or three weeks ago, but I'm just not sure if I'm too close to my next period that there's a chance I'm pregnant? I've gained about 2 - 3 lbs in the past week and my are feeling slightly tender. Someone told me that right before my period, I'm at my least fertile, but I keep reading lots of diff things. How long should I wait before taking a pregnancy test? Any other signs I can look out for? Any thoughts?Thanks!