Period or Pregnancy

I've been having headaches for the past few days, Even after I drink coffee ((I drink coffee everyday and without it I get migraines)) today I got extremely sick. My lower abdomin is having the worst cramps, as bad as it gets the first day on my period, which isn't due for another 4 days. I have a stomach ache and off and on headaches. A really bad period coming in or early pregnancy symptoms?