Missed period but now Im spotting and a slight cramp

Dominique

Ok guys help

I missed my period July 19 and its now August 7 and I started spotting and cramping yesterday . I took 3 pregnancy test and all of them came back negative . I took the test on the 3rd ,4th, and the 5th of August . Now Im confused because my periods almost never late not like this . Also its never this light . My last period was June 19th- 21st . I don't know what's going on HELP !