What Causes Light Bleeding When The Tubes Have Been Clamped?

I'm 31 years old I had my tubes clamped 4 years ago June 9th, when I use the bathroom and wipe I have a light color pink for the last day and once it was like regular blood and stopped and goes back to the light pink or nothing is there a chance I'm pregnant. I have also been sleepy a lot and a few other things just not sure if they go together.