Pms or pregnancy

It's too early for me to take a pregnancy test. I'm due for my period on the ninth so I can start testing on the fourth but I have been so emotional today. Way more than when I'm pmsing. I feel like I'm feeling every emotion there is and I'm so frustrated and then it makes me cry and I don't ever cry. I'm just confused. I had to go to the doctor yesterday and they took a pregnancy test but said it was negative. Could it have been too early? My boobs normally really hurt bad like unbearable when I'm pmsing but they haven't hurt at all. Just my nipples have been a little sore. Please help. I want to know what's going on and I can't find anything online and it's too early to test.