What Causes Slight Pinkish Discharge In Women?

My menstrual was a little different, medium, runny but not bad. After my menstrual went of somewhat, I began to have headaches and back pains. Even my legs felt as if my menstrual was about to come back on, cramping. Now I have a very slight discharge that is somewhat pinkish but not really. And I'm a little tired. What could be wrong with me?