Confuuuuuuused!

Arianny
My period was supposed to came June 19th. I'm still waiting. 12 days ago I took a pregnancy test and it was negative. 2 days ago I had headache, nauseas, some breast pain and today I have pain in my back so I went to the bathroom and I found this brown thing aaaaaand I already made another pregnancy test and it was negative too! I don't know what to do! HELP!