Do I still have a chance?

This is my calender. I took a test yesterday morning BFN FRER. then in the evening it was a very faint BFP instantly on a cheapie. But as the hours went by the line turned grayish and disappeared.. I took another test afterwards and it was a BFN. Then I took a test this morning it was also a BFN... I had cramping yesterday as well... AF not due till Sunday. What do you ladies think? Do I still have a chance? Did I test to early? :-/ I have a 37 cycle the latest my period come is cycle day 42