Pregnant or not

So I started my period on the 4th of this month I normally last 6 day always it's never been any longer ... this time its lasted 8 day with nothing but the urge to be sick and a massive constant head ache I took a pregnancy test when I was late for my period but came back negative ino some times you can bleed up to 12 weeks of been pregnant I haven't tested since has anyone ever had this problem with there period .....

I'm a little in the dark I would like some more input I feel sick to my stomach but I really dont think I'm pregnant....