What Causes Brown And Pink Spotting After Periods?

This past cycle was my first without Clomid or Letrazole, I am now almost a week last. I took an at home Pregnancy test after 2 days late and it was negative. About a week before my expected period I have ~4days of brown blood on the 4th day I had very light pink and then a few days later I had egg white consistancy mucus. I dont know what to think or do.