Body needs to make up its mind

I was supposed to have gotten my period already. I'm nearly 4 days late. I have had mild on and off cramping but only results in white discharge. I had unprotected sex on the last day of ovulation June 17th and my period was supposed to have been here on the 1st. I usually have mild break outs but my skin is mainly clear. My appetite even increased. now it's beginning to worry me. I took a pregnancy test the other day but it came to be negative....