What Causes Early Menstruation Along With Heavy Bleeding?

Hi I started spotting light pink 2weeks ago and then started my period 3 days early this month and the flow is very heavy. Any ideas? Could I be pregnant I just had a baby 6months ago and had him thru a placental abrubtion. Have 3 kids all together and last baby I bled heavy like this to flush out everything and I ended up pregnant. Do u think it an early sign of pregnancy?