Implantation or period

So on the calendar my period is suppose to be here September 1st and I got my period 7 days before it's due.. I was shocked when I was getting cramps then next thing u know I was bleeding! Now it was a lot of blood coming out and it was red then all of a sudden I put a pad on now about 2 hours later I look and it's not a lot on the pad but it's really dark like a dark brown. So now is this my period or implantation bleeding I'm so confused!! It's been 14 day past ovulation today. Not sure what's going on. It might just be my period come a whole week early but not sure. And my nipples kinda hurt but it maybe because of my "period" Also when I while it's really red