I had unprotected sex about two weeks ago, and I was suppose to get my period last saturday. And about on Wednesday, my breasts started getting really sore, and they're still sore. I'm having lower back pains every once in a while, mood swings and head aches. I feel like throwing up but I never do. I'm always extremely tired and I fall asleep in class, which I have never done that. And I pee a lot more than I usually do. Should I take a pregnancy test? And how accurate would it be??