I had my period almost 3 weeks ago and been cramping sometimes discharge ctaving food tired sometimes today feeling sick and sleepy help?

Multiple reasons why. 1. Depending on your age you may be experiencing early symptoms of "endometriosis" a condition that is related to worsening period cramps and menstrual irregularity. If this the only time you had a problem like you describe, you may have experienced a ruptured ovarian cyst. Other causes may include irritable bowel, urinary tract infection or other issues. Fatigue etc is other unrelated issues.