Ok so i had my last period on July 23th to July 27th. Then on August 1 i had sex with a condom but i know my partner put the tip of his condom on the wrong side first but he flipped it around before we.. you know.. But on August 18th (two days earlier than i expected) i started, what i think, is my period. It was dark brown and pretty light that day. The next day it was like my regular period, a medium flow. But on the 20th it was pretty light, barely anything was on the pad. Same thing happened today (the 21st). So from all of that can anyone tell me if i'm preg?? I know that precum has like less than 10% sperm but im still scared.