On 7/7, I had brown discharges with blood in it ( well, I dont really know if its blood. But its got red strains in it). Sometimes light , sometimes heavy, sometimes doesn't have the red stuff in it. And it last about 5 days. Could someone tell me is it normal??

Ps: my period was suppose to come 7/23, and I have done 4 pg-test, all came out negative. I have no symptoms at all, maybe just stress?? School, jobs. :(

thanks guys!