hi I am 25 years old and I have six kids and I am happily married after my husband and i had are twins we decided that i would get a tubal ligation so i did and its been two years now and i started my period a week earlier then normal last month and this month it started a week earlier then last month and it lasted about a day i have always been on time every month and i have taken three home pregnancy test and they all came back negative could i still be pregnant.