I had my period on the 15th of october it lasted 7 days and then for about a day and a half i had brown almost black discharge come out when i wiped and now i'm bleeding almost like a period but the blood is lighter in color i took a test it was neg?

Tests are accurate: A urine pregnancy test, done correctly, gives a reliable result by 3 weeks after sex (3 weeks after when conception might have occurred), 1 week after missing a period, or 1 week after getting a "weird" period . If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test. If worries, can call one's Ob-Gyn or PCP doctor.