Opinions: Could I be pregnant?

As you can see I have had fairly regular periods, always exactly 25 days apart. I was supposed to start my period the 15th of this month....but nothing! I've been having cramps, headaches, frequently having to pee, and a white-ish discharge. The hearts are when I had sex obviously, and the 31st was a 33% of getting pregnant as I was ovulating. But home pregnancy hcg tests have been negative. Opinions?