Negative test

My period was to begin on 12/12/15 and it did not. It is never late. Even after stopping BC after being on it for 14 years it came on CD 25 every month after. So Monday 12/14/15 I took 2 hpt and both came back negative so I figured to test again in a few days but in the mean time I have had cramping, a nagging headache off and on, and bloating. So today 12/16/15 I took two more test and again Both negative. But today I started to spot.