Am I Having A Miscarriage? I Did Not Know I

Am I having a miscarriage? I did not know I may have been pregnant, not have I ever been pregnant before. Days before any bleeding began I was very nauseous and had vomited. I began having a light brown/ pinkish discharge and then very sudden heavy bleeding began hours later with many larger than normal blood clots. Along with thing I was having sever back and abdominal cramping. This lasted about a day and the next day began with heavy bleeding, fewer clots and eventually lightened up and now I am back to the brown discharge with the same cramps.