14 days late.

So my periods are never always on time but never this late. I had unprotected sex on the 9th and was supposed to start on the 16th. I have yet to start. Although for almost a week I have been having bad cramps. Sometimes in my left side through to my back, some in the front and it feels like I'm going to start but still nothing. Life is very stressful right now (I mean it's life, when isn't it). I have taken several tests and all have said negative. Anyone else had this problem?