Helpp please

Ok so i had unprotected sex 3 times during my ovulation period . . totally forgetting thats when i ovulated. the past week i been having some symptoms i dont normally have for my period. my period was due yesterday 10/15, i bleed for less than a day the day before and it was gone that night, now nothing?! could it have been implantation bleeding? my period normally lasts 4 – 5 days. i took a test yesterday morning, the day it stopped and the day i was due but it was neg. it was also a generic cheap brand. please help! im sooo confusedd . . . i really appreciate all the advice i can get! ! ! thanks so muchhh . . :huh: