What Is The Irregular Brown Spotting After Discontinuing Depo Provera Shot?

hi, im 21 years old i weight about 100 pounds.about a year ago i got the shot for depo provera but decided to stop using it and now after that i've been having brown spotting and discharge sometimes along with clots between periods it is usually after or before my period and sometimes i dont experience this so i was wondering what this could mean?