Period or Implantation?

Le

I had my period 23-26. It was very light and I didn't get horrible cramping like I used to. Of the four days, two of them were extremely light and it was brown blood or discharge. Which usually happens on the last day only. Day two was probably the heaviest. During I was so nauseous. Ever since its ended, I'm extremely tired and have been cramping worse than I did when I was on my period. I tested the 26th in the evening and was negative. Any advice on this or if someone has had a similar experience