Help!

I started my period last 2 weeks, (May 30-June 3). I had unprotected sex June 9 and I took emergency contraceptive, Just in case. I've been feeling nauseous, dizzy, moody, and backache. Am I pregnant? Or Since I took the contraceptive, My period is supposed to come which I am spotting a little bit. Please help? Am I pregnant or My period came because I took the emergency contraceptive last week?