My last period was dec.30,2013. On jan.24 I started brown spotting it lasted 2-1/2 days it was accompanied by severe headaches, thirst, diahrhea, and constipation also some slight cramps. The symtoms lasted a week and a half and then were gone. I took 3 HPT and all were negative. I took one feb.4, feb.7, feb.8. On feb.9 I went to bathroom to make bowel movement and a while later noticed 2 bright red spot of blood in underwear so thought was period coming on and placed a tampon, only to find out sometime later that very light amount of brown blood and all bleeding has stopped again as of that night. Could I be pregnant or is this something else?