I'm very good about knowing when I should get my period. This month i got it three days early, which isn't that big of a deal but it put me on a 25 day cycle which is highly unusual for me. I have had unprotected sex with my partner since my last period. But after i got my period early, I realized it was very light. And then it disappeared. Just when i called him to tell him i was freaking out, it came back. It's been three days of my period coming in lightly, and then disappearing. I took a pregnancy test which was negative. What the heck is going on?