I got my period 3 days early... I am 28 day cycle usually but I don't know why it would come early. Last week I had pretty severe hunger pains in the middle of the night and the next five days I had headaches and nausea. Today I had sore nipples and back pain with a heavy period. I had unprotected sex with my BF within my ovulation window and o day as well. Please help, what could it be?