I am 20, My period is late 18 days, I took a pregnancy test last week and it was negative. I took another one Monday morning and it was negative. Monday night I had a brown discharge, and I thought It was my period coming but I havent gotten any blood at all. Today is thrusday I still have brown discharge but no period.My lower back is being hurting and my breast is tender, I have been having headaches a lot. Am I pregnant and it is just too early to tell with home pregnancy test? what should I do?