I Have Had Every Sign Of Pregnancy For Around Two

I have had every sign of pregnancy for around two weeks now. Started first with my boobs and nipples trying so bad, then nausea and heartburn and pretty much everything in the book. I was supposed to start my period on Sunday. I've had mild brown spotting for the last two days. I took a home pregnancy test today and it was negative. What's going on? Could I still be pregnant?