I Was A Week Late For My Period & Im

I was a week late for my period & im not usually late. I took a pregnancy test the 21st or 22nd & it was negative. I had heavy bleeding the night of the 26th but the 2 days following it was very light & pink to brown in color. my periods are usually normal 28 day cycle with a week on my period. I was just wondering if I could be pregnant.